Physical quantity measurement device and measurement control device

ABSTRACT

An air flow meter includes an inward part that is positioned inward of an intake pipe and an outward part that is positioned not inward but outward of the intake pipe. The air flow meter further includes a first detector provided in the inward part, and a second detector provided at a position closer to the outward part than the first detector.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of InternationalPatent Application No. PCT/JP2018/025186 filed on Jul. 3, 2018, whichdesignated the U.S. and claims the benefit of priority from JapanesePatent Application No. 2017-142855 filed on Jul. 24, 2017, and JapanesePatent Application No. 2017-247429 filed on Dec. 25, 2017. The entiredisclosures of all of the above applications are incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates to a physical quantity measurement deviceand a measurement control device.

BACKGROUND

A physical quantity measurement device measures a flow rate of intakeair taken into an internal combustion engine. The physical quantitymeasurement device includes a main passage through which an inflow fluidpasses, and a bypass passage branched from the main passage. A flow ratedetector for outputting a detection signal corresponding to the flowrate of intake air is provided in the bypass passage.

SUMMARY

According to at least one embodiment of the present disclosure, aphysical quantity measurement device measures a physical quantity of afluid. The physical quantity measurement device includes a measurementflow channel through which the fluid as a measurement target flows, anda housing that forms the measurement flow channel and is attached to apredetermined attaching target in a state where at least a part of thehousing is positioned inward of the attaching target. The physicalquantity measurement device includes a physical quantity detector thatdetects a physical quantity of the fluid in the measurement flowchannel, and a same kind-quantity detector that detects, in an interiorof the housing, a physical quantity of the same kind as the physicalquantity detected by the physical quantity detector. The physicalquantity detected by the same kind-quantity detector is a correctionparameter used for correcting a detection result of the physicalquantity detector. The physical quantity measurement device includes aninward part that is positioned inward of the attaching target, and anoutward part that is positioned outward of the attaching target withoutbeing positioned inward of the attaching target. The physical quantitydetector is provided at a position included in the inward part. The samekind-quantity detector is provided at a position closer to the outwardpart than the physical quantity detector is in an alignment directionalong which the inward part and the outward part are aligned.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating a configuration of acombustion system according to a first embodiment.

FIG. 2 is a front view of an air flow meter in a state of being attachedto an intake pipe.

FIG. 3 is a top view of an air flow meter in a state of being attachedto the intake pipe.

FIG. 4 is a perspective view of the air flow meter as seen from anupstream-side end face of the air flow meter.

FIG. 5 is a perspective view of the air flow meter as seen from adownstream-side end face of the air flow meter.

FIG. 6 is a side view of the air flow meter as viewed from a connectorportion side.

FIG. 7 is a side view of the air flow meter as viewed from a sideopposite to the connector portion.

FIG. 8 is a cross-sectional view taken along a line VIII-VIII of FIG. 2.

FIG. 9 is an enlarged view of a periphery of a measurement flow channelof FIG. 8.

FIG. 10 is a front view showing a configuration of a sensor SA.

FIG. 11 is a cross-sectional view taken along a line XI-XI of FIG. 8.

FIG. 12 is a cross-sectional view taken along a line XII-XII of FIG. 8.

FIG. 13 is a cross-sectional view taken along a line XIII-XIII of FIG.8.

FIG. 14 is a cross-sectional view taken along a line XIV-XIV of FIG. 8.

FIG. 15 is a horizontal cross-sectional view of a housing before thesensor SA is inserted into the housing.

FIG. 16 is a horizontal cross-sectional view of the sensor SA prior toinsertion into the housing.

FIG. 17 is a vertical cross-sectional view showing an internalconfiguration of the sensor SA.

FIG. 18 is a diagram illustrating a connection structure between aconnector terminal and a lead terminal of the sensor SA.

FIG. 19 is a perspective view showing an internal structure of a sealingregion.

FIG. 20 is a perspective view of a terminal unit.

FIG. 21 is an enlarged view of a periphery of a lip in FIG. 8.

FIG. 22 is an exploded perspective view of a mold device.

FIG. 23 is a diagram illustrating molding of a measurement flow channelby a measurement molding portion.

FIG. 24 is a view showing a state in which the measurement moldingportion is removed from the housing.

FIG. 25 is a diagram illustrating molding of a passage flow channel by apassage mold portion.

FIG. 26 is a view showing a state in which the passage mold portion andthe measurement molding portion are removed from the housing.

FIG. 27 is a side view of an air flow meter in a configuration group Bas viewed from a connector portion side.

FIG. 28 is a cross-sectional view taken along a line XXVIII-XXVIII ofFIG. 27.

FIG. 29 is an enlarged view of a periphery of a sensor SA in FIG. 8 in aconfiguration group C.

FIG. 30 is a cross-sectional view taken along a line XXX-XXX of FIG. 29.

FIG. 31 is a cross-sectional view taken along a line XXXI-XXXI of FIG.29.

FIG. 32 is a view showing a state in which the measurement moldingportion and the passage mold portion are removed from the housing in aconfiguration group D.

FIG. 33 is a diagram illustrating the molding of the passage flowchannel by the measurement molding portion and the passage mold portion.

FIG. 34 is an enlarged view of a periphery of the sensor SA in FIG. 30in a configuration group E.

FIG. 35 is a top view of the air flow meter showing an internalstructure of the housing.

FIG. 36 is an enlarged view of the periphery of the connector moldportion in a mold device.

FIG. 37 is a view illustrating the attachment of the sensor SA to thehousing.

FIG. 38 is a diagram illustrating the attachment of a bridge terminal tothe sensor SA.

FIG. 39 is a diagram illustrating filling of a thermosetting resin intoan internal space of the housing.

FIG. 40 is a top view of the air flow meter in a configuration group F.

FIG. 41 is a cross-sectional view taken along a line XLI-XLI of FIG. 40.

FIG. 42 is an enlarged view of a lip periphery of FIG. 41.

FIG. 43 is a perspective view of a potting portion of the air flow meterin a configuration group G.

FIG. 44 is a vertical cross-sectional view of the air flow meterattached to an intake pipe in a configuration group H.

FIG. 45 is a side view of the air flow meter as viewed from theconnector portion side.

FIG. 46 is a block diagram showing an electrical configuration of atemperature correction unit.

FIG. 47 is a diagram illustrating processing in a first correction unit.

FIG. 48 is a diagram showing a relationship between a flow rate signaland a time constant.

FIG. 49 is a diagram showing temporal changes of a first correctionsignal when a flow rate is large and when the flow rate is small.

FIG. 50 is a diagram showing a temporal change of each of a firsttemperature signal and the first correction signal.

FIG. 51 is a diagram showing a temporal change of each of the firsttemperature signal and the second temperature signal.

FIG. 52 is a diagram showing a temporal change of each of a temperaturedifferential signal and a differential correction signal.

FIG. 53 is a diagram showing a relationship between the temperaturedifferential signal and the differential correction signal.

FIG. 54 is a diagram showing temporal changes of the first temperaturesignal, the second temperature signal, and the first correction signalin a configuration different from that of the first embodiment.

FIG. 55 is a diagram showing a temporal change of each of thetemperature differential signal and the differential correction signalin a configuration different from that of the first embodiment.

FIG. 56 is a diagram showing a temporal change of each of the firsttemperature signal, the first correction signal, and a correction valuesignal.

FIG. 57 is a diagram showing a temporal change of each of the firsttemperature signal, the first correction signal, the correction valuesignal, and an actual temperature.

FIG. 58 is a horizontal cross-sectional view of the housing around adetection throttle portion according to a second embodiment.

FIG. 59 is a horizontal cross-sectional view of the housing around alongitudinal partition wall.

FIG. 60 is a horizontal cross-sectional view of an air flow meter arounda housing protrusion according to a third embodiment.

FIG. 61 is a side view of an air flow meter in a state of being attachedto an intake pipe according to a fourth embodiment.

FIG. 62 is a front view of the air flow meter.

FIG. 63 is a cross-sectional view taken along a line LXIII-LXIII line ofFIG. 61.

FIG. 64 is a view showing an internal structure of the housing in astate where the potting portion and the cover member are removed.

FIG. 65 is a view showing a base member.

FIG. 66 is a view illustrating the attachment of a cover to the basemember.

FIG. 67 is a view illustrating the attachment of a sensor SA to ahousing body.

FIG. 68 is a view illustrating the formation of the potting portion inthe housing.

FIG. 69 is a perspective view of a first regulation portion in aconfiguration group C.

FIG. 70 is an enlarged view of the periphery of a flow rate detector inFIG. 63.

FIG. 71 is a cross-sectional view taken along a line LXXI-LXXI of FIG.70.

FIG. 72 is a vertical cross-sectional view of an air flow meter inconfiguration groups E and F.

FIG. 73 is a front view of an air flow meter in a configuration group G.

FIG. 74 is a vertical cross-sectional view of the housing around apassage flow channel in a configuration group D according to a fifthembodiment.

FIG. 75 is a cross-sectional view taken along a line LXXV-LXXV of FIG.74.

FIG. 76 is a diagram illustrating the molding of the passage flowchannel by the measurement molding portion and the passage mold portion.

FIG. 77 is a cross-sectional view taken along a line LXXVII-LXXVII ofFIG. 76.

FIG. 78 is a view showing a state in which a measurement molding portionis removed from the housing prior to the passage mold portion.

FIG. 79 is a view showing a state in which the passage mold portion isremoved from the housing after the measurement molding portion.

FIG. 80 is a vertical cross-sectional view of a housing in aconfiguration group E according to a sixth embodiment.

FIG. 81 is a view illustrating the attachment of the sensor SA to thehousing.

FIG. 82 is a side view of an air flow meter in a state of being attachedto an intake pipe in Modification B1.

FIG. 83 is a cross-sectional view taken along a line LXXXIII-LXXXIIIline of FIG. 82.

FIG. 84 is a horizontal cross-sectional view of a housing inModification B3.

FIG. 85 is a horizontal cross-sectional view of the housing inModifications B2 and B3.

FIG. 86 is a horizontal cross-sectional view of the housing inModification B3.

FIG. 87 is a horizontal cross-sectional view of a housing inModification B4.

FIG. 88 is a vertical cross-sectional view of an air flow meter in astate of being attached to an intake pipe in Modification B5.

FIG. 89 is a vertical cross-sectional view of a periphery of a sensor SAin Modification C1.

FIG. 90 is a vertical cross-sectional view of the periphery of thesensor SA in Modification C2.

FIG. 91 is a perspective view of a positioning member.

FIG. 92 is a view showing an internal structure of a housing in a statein which a potting portion and a cover member are removed inModification C3.

FIG. 93 is a diagram illustrating the molding of a passage flow channelby a measurement molding portion, an inflow passage mold portion, and anoutflow passage mold portion in Modification D1.

FIG. 94 is a view showing a state in which the measurement moldingportion, the inflow passage mold portion, and the outflow passage moldportion are removed from the housing.

FIG. 95 is a diagram illustrating the molding of the passage flowchannel by the measurement molding portion and the passage mold portionin Modification D2.

FIG. 96 is a vertical cross-sectional view of the housing around thepassage flow channel in Modification D4.

FIG. 97 is a vertical cross-sectional view of a housing in ModificationsE1 and E2.

FIG. 98 is a vertical cross-sectional view of the housing inModifications E1 to E3.

FIG. 99 is a vertical cross-sectional view of the housing inModifications E2 and E3.

FIG. 100 is a view showing an internal structure of the housing in astate in which the potting portion and the cover member are removed inModification E4.

FIG. 101 is a vertical cross-sectional view of the housing in which thebase member and the sensor SA are disassembled.

FIG. 102 is a vertical cross-sectional view of a housing in which a basemember and a cover unit are disassembled in Modification E5.

FIG. 103 is a vertical cross-sectional view of the housing inModification E6.

FIG. 104 is a side view of the housing.

FIG. 105 is a vertical cross-sectional view of the housing.

FIG. 106 is a vertical cross-sectional view of the housing inModification F1.

FIG. 107 is a vertical cross-sectional view of the housing.

FIG. 108 is an enlarged view of the periphery of a lip periphery inModification F2.

FIG. 109 is an enlarged view of the periphery of the lip in ModificationF3.

FIG. 110 is an enlarged view of the periphery of the lip.

FIG. 111 is an enlarged view of the periphery of the lip in ModificationF4.

FIG. 112 is an enlarged view of the periphery of a lip in ModificationF5.

FIG. 113 is an enlarged view of the periphery of the lip.

FIG. 114 is a vertical cross-sectional view of an air flow meter in astate of being attached to an intake pipe in Modification H1.

FIG. 115 is a block diagram showing an electrical configuration of atemperature correction unit in Modification H2.

FIG. 116 is a block diagram showing an electrical configuration of atemperature correction unit in Modification H3.

FIG. 117 is a block diagram showing an electrical configuration of atemperature correction unit in Modification H4.

FIG. 118 is a block diagram showing an electrical configuration of atemperature correction unit in Modifications H5 and H7.

FIG. 119 is a block diagram showing an electrical configuration of atemperature correction unit in Modifications H6 and H7.

FIG. 120 is a horizontal cross-sectional view of a housing inModification B4.

FIG. 121 is an enlarged view of a periphery of a lip in Modification F6.

DETAILED DESCRIPTION

According to a first aspect of the present disclosure, a physicalquantity measurement device measures a physical quantity of a fluid. Thephysical quantity measurement device includes a measurement flow channelthrough which the fluid as a measurement target flows, and a housingthat forms the measurement flow channel and is attached to apredetermined attaching target in a state where at least a part of thehousing is positioned inward of the attaching target. The physicalquantity measurement device includes a physical quantity detector thatdetects a physical quantity of the fluid in the measurement flowchannel, and a same kind-quantity detector that detects, in an interiorof the housing, a physical quantity of the same kind as the physicalquantity detected by the physical quantity detector. The physicalquantity detected by the same kind-quantity detector is a correctionparameter used for correcting a detection result of the physicalquantity detector. The physical quantity measurement device includes aninward part that is positioned inward of the attaching target, and anoutward part that is positioned outward of the attaching target withoutbeing positioned inward of the attaching target. The physical quantitydetector is provided at a position included in the inward part. The samekind-quantity detector is provided at a position closer to the outwardpart than the physical quantity detector is in an alignment directionalong which the inward part and the outward part are aligned.

Heat may transfers from an external heat source, such as an internalcombustion engine or the like existing around the attaching target, tothe outward part of the housing. If the heat is applied to the physicalquantity detector through the housing, an error between the detectionresult of the physical quantity detector and the actual physicalquantity may become large. In other words, an accuracy in measurement ofthe physical quantity may decrease.

On the other hand, according to the first aspect, since the samekind-quantity detector is provided at a position closer to the externalheat source than the physical quantity detector is, a degree of heatapplication indicating a degree of heat applied from the external heatsource is likely to be different between the same kind-quantity detectorand the physical quantity detector. In addition, since the detectionresult of the same kind-quantity detector is used as a correctionparameter to correct the detection result of the physical quantitydetector, the measured value of the physical quantity can be acquired.In this case, by using the fact that the difference in degree of heatapplication is easily reflected in the difference between the detectionresult of the same kind-quantity detector and the detection result ofthe physical quantity detector, an error between the measured value ofthe physical quantity and the actual physical quantity can be reduced.Therefore, the measurement accuracy of the physical quantity can beenhanced.

According to a second aspect of the present disclosure, a measurementcontrol device controls a physical quantity measurement device. Thephysical quantity measurement device includes a measurement flow channelthrough which a fluid as a measurement target flows, and a housing thatforms the measurement flow channel and is attached to a predeterminedattaching target in a state where at least a part of the housing ispositioned inward of a predetermined attaching target. The physicalquantity measurement device includes a physical quantity detector thatdetects a physical quantity of the fluid in the measurement flowchannel, and a same kind-quantity detector that detects, in an interiorof the housing, a physical quantity of the same kind as the physicalquantity detected by the physical quantity detector. The physicalquantity measurement device includes an inward part that is positionedinward of the attaching target, and an outward part that is positionedoutward of the attaching target without being positioned inward of theattaching target. The physical quantity detector is provided at aposition included in the inward part. The same kind-quantity detector isprovided at a position closer to the outward part than the physicalquantity detector is in an alignment direction along which the inwardpart and the outward part are aligned. The measurement control devicefurther comprises a physical quantity correction unit that corrects adetection result of the physical quantity detector based on a detectionresult of the same kind-quantity detector.

According to the second aspect, since the detection result of thephysical quantity detector is corrected based on the correction resultof the same kind-quantity detector, an accuracy in measurement of thephysical quantity can be enhanced similarly to the first embodiment.

According to a third aspect of the present disclosure, a measurementcontrol device controls a physical quantity measurement device. Thephysical quantity measurement device includes a measurement flow channelthrough which a fluid as a measurement target flows, a housing thatforms the measurement flow channel and is attached to a predeterminedattaching target, and a physical quantity detector that detects aphysical quantity of the fluid in the measurement flow channel. Themeasurement control device includes a change correction unit thatcorrects a detection result of the physical quantity detector based on abehavior of change of the detection result of the physical quantitydetector.

Heat may transfer to the housing from the external heat source, such asan internal combustion engine existing around the attaching target. Ifthe heat is applied to the physical quantity detector through thehousing, a delay may occur until the detection result of the physicalquantity detector indicates a result corresponding to an actual physicalquantity. In other words, the response delay of the measurement of thephysical quantity may occur, as a result of which, an accuracy inmeasurement of the physical quantity may be lowered.

On the other hand, according to the third aspect, since the behavior ofchange of the detection result of the physical quantity detector is usedfor the correction by the change correction unit, the change correctionunit predicts the behavior of change of the detection result. Thus, atime required for the correction result of the change correction unit toreach the result corresponding to the actual physical quantity can bereduced as compared with a time required for the detection result of thephysical quantity detector to reach the result corresponding to theactual physical quantity. Therefore, the response delay of the physicalquantity measurement can be reduced, and as a result, an accuracy inmeasurement of the physical quantity can be enhanced.

Hereinafter, multiple embodiments for implementing the presentdisclosure will be described referring to drawings. In the respectiveembodiments, a part that corresponds to a matter described in apreceding embodiment may be assigned the same reference numeral, andredundant explanation for the part may be omitted. When only a part of aconfiguration is described in an embodiment, another precedingembodiment may be applied to the other parts of the configuration. Theparts may be combined even if it is not explicitly described that theparts can be combined. The embodiments may be partially combined even ifit is not explicitly described that the embodiments can be combined,provided there is no harm in the combination.

First Embodiment

A combustion system 10 shown in FIG. 1 includes an internal combustionengine 11 such as a gasoline engine, an intake passage 12, an exhaustpassage 13, an air flow meter 14, and an ECU 20, and the combustionsystem 10 is mounted on a vehicle, for example. The air flow meter 14 isprovided in the intake passage 12, and has a function of measuringphysical quantities such as a flow rate, a temperature, a humidity, anda pressure of an intake air supplied to the internal combustion engine11. The air flow meter 14 corresponds to a physical quantity measurementdevice for measuring the intake air as a fluid. The intake air is a gassupplied to a combustion chamber 11 a of the internal combustion engine11. In the combustion chamber 11 a, a mixture of the intake air and afuel is ignited by an ignition plug 17.

The ECU (Engine Control Unit) 20 is a control device for controlling theoperation of the combustion system 10. The ECU 20 is a calculationprocessing circuit including a processor, a storage medium such as aRAM, a ROM and a flash memory, a microcomputer including an input andoutput unit, a power supply circuit, and the like. The ECU 20 receives asensor signal output from the air flow meter 14, sensor signals outputfrom a large number of vehicle-mounted sensors, and the like. The ECU 20performs an engine control on a fuel injection amount, an EGR amount,and the like of an injector 16 with the use of the measurement result bythe air flow meter 14. The ECU 20 is a control device for controllingthe operation of the internal combustion engine 11, and the combustionsystem 10 may be referred to as an engine control system. The ECU 20corresponds to an external device.

The air flow meter 14 is one of a large number of measurement unitsincluded in the combustion system 10. In an intake system and an exhaustsystem of the internal combustion engine 11, for example, an air-fuelratio sensor 18 and the like are provided in addition to the air flowmeter 14 as a measurement unit. The air flow meter 14 is disposed on adownstream side of an air cleaner 19 and an upstream side of a throttlevalve 15 in the intake passage 12. In that case, with respect to the airflow meter 14 in the intake passage 12, the air cleaner 19 side is onthe upstream side, and the combustion chamber 11 a side is on thedownstream side.

The air flow meter 14 shown in FIGS. 2 and 3 is detachably attached toan intake pipe 12 a defining the intake passage 12. The air flow meter14 is inserted into an airflow insertion hole 12 b provided so as topenetrate through a cylindrical wall of the intake pipe 12 a, and atleast a part of the air flow meter 14 is located in the intake passage12. The intake pipe 12 a has a pipe flange 12 c extending from theairflow insertion hole 12 b toward an outer peripheral side, andincludes a pipe made of a synthetic resin material or the like. A pipeflange 12 c extends along a peripheral portion of the airflow insertionhole 12 b, and is formed in an annular shape, for example. A tip endface of the pipe flange 12 c extends in a direction orthogonal to acenter line of the pipe flange 12 c. In that case, the tip end face ofthe pipe flange 12 c extends in a longitudinal direction of the intakepassage 12, that is, in a direction in which the intake air flows in theintake passage 12. The intake pipe 12 a corresponds to an attachingtarget.

The air flow meter 14 includes a housing 21, a flow rate detector 22(refer to FIG. 8), and an intake air temperature sensor 23. The housing21 is made of, for example, a resin material or the like. In the airflow meter 14, since the housing 21 is attached to the intake pipe 12 a,the flow rate detector 22 is brought into contact with the intake airflowing through the intake passage 12. The housing 21 includes a housingbody 24, a ring holding portion 25, a flange portion 27, a connectorportion 28, a root portion 29 a, and a protective protrusion 29 b, andan O-ring 26 is attached to the ring holding portion 25. The housingbody 24, the ring holding portion 25, the flange portion 27, theconnector portion 28, the root portion 29 a, and the protectiveprotrusion 29 b are manufactured by a single resin molding process,which will be described later, in order to realize cost reduction.

As shown in FIGS. 2 to 7, the housing body 24 is formed in a cylindricalshape as a whole, and in the housing 21, the ring holding portion 25,the flange portion 27, the connector portion 28, the root portion 29 a,and the protective protrusion 29 b are integrally provided in thehousing body 24. When a width direction X, a height direction Y, and adepth direction Z are defined in the air flow meter 14, the housing body24 extends in the height direction Y, and the ring holding portion 25and the flange portion 27 extend from the housing body 24 in the widthdirection X and the depth direction Z. The ring holding portion 25, theflange portion 27, and the connector portion 28 are disposed on a baseend side of the housing 21 with respect to the housing body 24.Hereinafter, the base end side of the housing 21 is also referred to asa housing base end side, and a tip side of the housing 21 is alsoreferred to as a housing tip side. In other words, in the heightdirection Y, a housing base end face 192 (shown in the drawing) side,which will be described later, is referred to as the housing base endside, and a housing tip end face 191 side is referred to as a housingtip side. The housing base end face 192 may be referred to as a base endor a base end portion of the housing 21, and the housing tip end face191 may be referred to as a tip or a tip portion of the housing 21. Thewidth direction X, the height direction Y, and the depth direction Z areorthogonal to each other.

The ring holding portion 25 is a portion that is fitted into the airflowinsertion hole 12 b through the O-ring 26. The ring holding portion 25has a holding groove 25 a circumferentially extending along theperiphery of the housing body 24, and holds the O-ring 26 in a state inwhich the O-ring 26 is inserted into the holding groove 25 a. The ringholding portion 25 has a pair of groove defining portions protruding inthe width direction X and the depth direction Z, and the groove definingportions are spaced apart from each other in the height direction Y, sothat the holding groove 25 a is defined between the groove definingportions. The pair of groove defining portions may also be referred toas seal guide walls.

The O-ring 26 is a member for sealing the intake passage 12 and theoutside of the intake pipe 12 a. The O-ring 26 is fitted externally tothe ring holding portion 25, and is interposed between the ring holdingportion 25 and the airflow insertion hole 12 b in a state of entering aninner peripheral side of the pipe flange 12 c.

The flange portion 27 is disposed closer to the housing base end sidethan the ring holding portion 25, and covers the airflow insertion hole12 b from the outer peripheral side of the intake pipe 12 a. Further,the flange portion 27 can restrict the housing 21 from excessivelyentering the intake passage 12 by being caught by the tip portion of thepipe flange 12 c of the intake pipe 12 a. The connector portion 28surrounds multiple connector terminals 28 a (refer to FIG. 6), andcorresponds to a terminal protection portion for protecting theconnector terminals 28 a. A plug portion is inserted into the connectorportion 28. The plug portion is provided at an end portion of aconnecting line which are electrically connected directly or indirectlyto the ECU 20 and mates with the connector portion 28.

The housing 21 is formed with multiple thinned portions 41 for improvinga dimensional accuracy and reducing a weight after molding. The thinnedportions 41 are provided, for example, on the flange portion 27, thehousing body 24, and the ring holding portion 25. In addition, when thehousing 21 is molded with resin, a thickness of the housing 21 isappropriately thinned by the thinned portions 41, so that a portion inwhich a molten resin does not flow is hardly generated in the moldportion such as a mold. Further, the deterioration of dimensionalaccuracy that occurs due to cooling and shrinkage of the resin componentafter molding can be inhibited. Multiple screw holes 42 are provided inthe flange portion 27, and the housing 21 is fixed to the intake pipe 12a with the use of the screw holes 42. The intake pipe 12 a is providedwith bosses 12 d to which screw members (not shown) passing through thescrew holes 42 are mounted, and the flange portion 27 is supported bythe bosses 12 d. Each of the bosses 12 d extends along the pipe flange12 c from the outer peripheral surface of the intake pipe 12 a, and isdisposed at a position separated from the pipe flange 12 c. The bosses12 d may be provided integrally with the pipe flange 12 c.

The root portion 29 a protrudes from the ring holding portion 25 towardthe housing tip side in the height direction Y, and is disposed at aposition laterally separated from the housing body 24 in the widthdirection X in order to avoid the influence of a heat of the housingbody 24 which has received the heat from the engine and has risen intemperature. The intake air temperature sensor 23 includes a temperaturesensing element 23 a for sensing the temperature of the intake air, apair of lead wires 23 b extending from the temperature sensing element23 a, and a pair of intake air temperature terminals 23 c connected tothe lead wires 23 b. The pair of intake air temperature terminals 23 cextend from the root portion 29 a, and the temperature sensing element23 a is put across the pair of intake air temperature terminals 23 cthrough the pair of lead wires 23 b. Both the lead wires 23 b and theintake air temperature terminals 23 c have conductivity, and the intakeair temperature terminals 23 c are electrically connected to theconnector terminals 28 a (refer to FIG. 18) provided in the connectorportion 28. The intake air temperature terminals 23 c may be connectedto a bridge terminal 86 to be described later. Although not shown in thedrawing, in another embodiment, the lead wires 23 b and the intake airtemperature terminals 23 c may be integrated together. The intake airtemperature sensor 23 outputs a detection signal corresponding to theintake air temperature sensed by the temperature sensing element 23 a.

The protective protrusion 29 b protrudes laterally from the housing body24 in the width direction X, and is disposed closer to the housing tipside than the intake air temperature sensor 23. A protrusion dimensionof the protective protrusion 29 b from the housing body 24 is largerthan a separation distance of the intake air temperature sensor 23 fromthe housing body 24. In that case, when the housing 21 is viewed fromthe tip side, the intake air temperature sensor 23 is seen to overlapwith a back side of the protective protrusion 29 b. For that reason,when the housing 21 is inserted into the airflow insertion hole 12 bwhen the air flow meter 14 is attached to the intake pipe 12 a, even ifthe insertion position of the housing 21 is deviated in the widthdirection X, the protective protrusion 29 b comes into contact with theouter peripheral surface of the intake pipe 12 a. Therefore, the intakeair temperature sensor 23 is restrained from being damaged by the intakeair temperature sensor 23 coming into contact with the outer peripheralsurface of the intake pipe 12 a.

As shown in FIG. 8, the housing body 24 defines a bypass flow channel 30through which a part of the intake air flowing through the intakepassage 12 flows. The bypass flow channel 30 has a passage flow channel31 and a measurement flow channel 32, and the passage flow channel 31and the measurement flow channel 32 are defined by an internal space ofthe housing body 24. The passage flow channel 31 penetrates through thehousing body 24 in the depth direction Z, and includes an inflow port 33a as an upstream end portion and an outflow port 33 b as a downstreamend portion. The measurement flow channel 32 is a branch flow channelbranched from an intermediate portion of the passage flow channel 31,and has a measurement outlet 33 c which is a downstream end portion. Theintake passage 12 may be referred to as a main passage, and the bypassflow channel 30 may be referred to as a sub-passage. In FIG. 8, theO-ring 26 is not shown.

Returning to the description of FIGS. 2 to 7, in the housing body 24,the inflow port 33 a is provided on an upstream-side end face of thehousing body 24, and the outflow port 33 b is provided on adownstream-side end face of the housing body 24. Further, onemeasurement outlet 33 c is provided on each of both side surfaces of thehousing body 24. The measurement outlets 33 c have an elongated shapeextending in the height direction Y, and are aligned side by side in thewidth direction X. A side surface of the housing body 24 has a flatsurface 44 extending straight in the height direction Y and the depthdirection Z, and an upstream-side end face of the housing body 24 has acurved surface 45 curved so as to bulge toward the upstream side. Theflat surface 44 and the curved surface 45 are adjacent to each other inthe depth direction Z, and the measurement outlets 33 c are disposed ata position across a boundary between the flat surface 44 and the curvedsurface 45 in the depth direction Z on the side surface of the housingbody 24.

In this example, unlike the present embodiment, in the configuration inwhich all of the measurement outlets 33 c are opened to the curvedsurface 45 of the upstream-side end face, the measurement outlets 33 care susceptible to the dynamic pressure on the upstream side of theintake passage 12. As a result, there is a concern that a flow rateflowing into the measurement flow channel 32 from the passage flowchannel 31 is unintentionally reduced, and foreign matter such as dustenters the measurement flow channel 32 from the measurement outlet 33 c.

Further, at the boundary between the flat surface 44 and the curvedsurface 45 in the housing body 24, the intake air is likely to beseparated because a direction of advancement of the intake air flowingalong the flat surface 44 at the upstream-side end portion changes atthe flat surface 44. For that reason, unlike the present embodiment, inthe configuration in which all of the measurement outlets 33 c areopened to the flat surface 44 of the side surface, the measurementoutlet 33 c is affected by the separation of the intake air generated atthe boundary between the flat surface 44 and the curved surface 45, andthere is a concern that a flow velocity in the measurement flow channel32 becomes unstable.

In contrast to the above configurations, in the configuration in whichthe measurement outlet 33 c is disposed across the flat surface 44 andthe curved surface 45 as in the present embodiment, there is anadvantage that the measurement outlet 33 c is less susceptible to theeffect of a dynamic pressure on the upstream side of the intake passage12 and the separation of the intake air. In that case, the measurementoutlet 33 c is disposed at a position in which the influence of thedynamic pressure received from the upstream side of the intake passage12 and the influence of the separation of a gas flowing through theintake passage 12 are balanced with each other. Further, theabove-mentioned advantage is further increased by shortening themeasurement outlet 33 c as much as possible in the depth direction Z,and from the viewpoint of increasing the advantage, it is preferablethat the measurement outlet 33 c has an elongated shape in the heightdirection Y as in the present embodiment.

As shown in FIGS. 8 and 9, the passage flow channel 31 has an inflowpassage 31 a extending straight from the inflow port 33 a and an outflowpassage 31 b extending straight from the outflow port 33 b. The inflowpassage 31 a extends in the depth direction Z, while the outflow passage31 b extends in a direction inclined with respect to the depth directionZ. The outflow passage 31 b is inclined toward the outflow port 33 b tothe housing base end side, with the result that the outflow port 33 b isdisposed at a position deviated from the inflow port 33 a toward thehousing base end side.

The passage flow channel 31 is configured to be narrowed toward theoutflow port 33 b. In other words, the passage flow channel 31 isconfigured not to be narrowed even when approaching the inflow port 33 afrom the outflow port 33 b in the depth direction Z. The flow channelarea of the inflow passage 31 a is uniform in the depth direction Z. Inthe inflow passage 31 a, both the height dimension in the heightdirection Y and the width dimension in the width direction X are uniformin the depth direction. On the other hand, a cross-sectional area of theoutflow passage 31 b gradually decreases toward the outflow port 33 b.In the outflow passage 31 b, the height dimension is uniform in thedepth direction Z, while the width dimension gradually decreases towardthe outflow port 33 b.

A flow channel area of the passage flow channel 31 is a cross-sectionalarea of the passage flow channel 31 in a direction orthogonal to acenter line of the passage flow channel 31 or a direction in which thepassage flow channel 31 extends. The center line of the inflow passage31 a extends in the depth direction Z, and the center line of theoutflow passage 31 b is slightly inclined with respect to the depthdirection Z.

As shown in FIGS. 4 to 7, the housing body 24 has a passage throttleportion 47 for throttling the width dimension of the outflow passage 31b, and a throttle configuration of the passage flow channel 31 isrealized by the passage throttle portion 47. The housing body 24 has aconstriction portion 48 that gradually constricts the side surface andthe downstream-side end face of the housing body 24 toward the passagethrottle portion 47. With the provision of the constriction portion 48,an inner wall surface of the passage throttle portion 47 and an innerwall surface of an introduction path 32 b can be connected to each otherwithout a step. As a result, a separation flow at the connection portionbetween the outflow passage 31 b and the introduction path 32 b can beinhibited from occurring, and the measurement accuracy is improved.

Returning to the description of FIGS. 8 and 9, a flow channel boundaryportion 34, which is a boundary between the passage flow channel 31 andthe measurement flow channel 32, is a boundary between the outflowpassage 31 b and the measurement flow channel 32. The flow channelboundary portion 34 includes a measurement inlet which is an upstreamend portion of the measurement flow channel 32. In the depth directionZ, a length dimension of the flow channel boundary portion 34 is thesame as the length dimension of the outflow passage 31 b. In that case,the flow channel boundary portion 34 is not exposed from the inflow port33 a in the depth direction Z because the inflow port 33 a side of theflow channel boundary portion 34 is disposed closer to the housing tipside. In this example, in the inner peripheral surface of the passageflow channel 31, a surface of the housing base end side is referred toas a ceiling surface, and a surface of the tip side is referred to as abottom surface. In that case, when the outflow port 33 b is viewed fromthe upstream side in the depth direction Z, the flow channel boundaryportion 34 is hidden on a back side of a ceiling surface of the inflowpassage 31 a so as to be invisible. As a result, even if foreign mattersuch as dust, dust, waterdrops, or oil drops fly off along with theintake air, the foreign matter travels straight through the passage flowchannel 31 and is discharged from the outflow port 33 b, so that theforeign matter can be prevented from breaking the detection element 22 bwithout reaching the flow rate detector 22, and the foreign matter canbe prevented from accumulating to deteriorate the detection accuracy.

The measurement flow channel 32 has a folded shape folded back at anintermediate position. The measurement flow channel 32 includes adetection path 32 a provided with the flow rate detector 22, anintroduction path 32 b for introducing the intake air into the detectionpath 32 a, and a discharge path 32 c for discharging the intake air fromthe detection path 32 a. The introduction path 32 b extends from theflow channel boundary portion 34 toward the housing base end side, andthe discharge path 32 c extends from the measurement outlet 33 c towardthe housing base end side. The introduction path 32 b and the dischargepath 32 c extend in parallel with each other in the height direction Y,and the respective flow channel areas of the introduction path 32 b andthe discharge path 32 c are uniform in the height direction Y. In theintroduction path 32 b and the discharge path 32 c, both the widthdimension in the width direction X and the depth dimension in the depthdirection Z are uniform in the height direction. In that case, theintroduction path 32 b and the discharge path 32 c are not narrowed evenwhen approaching the housing base end side.

The flow channel area of the measurement flow channel 32 is across-sectional area of the measurement flow channel 32 in a directionorthogonal to the center line of the measurement flow channel 32. Thecenter lines of the introduction path 32 b and the discharge path 32 cextend in the height direction Y, and the center line of the detectionpath 32 a extends in the depth direction Z. The height direction Y inwhich the introduction path 32 b and the discharge path 32 c extendcorresponds to a direction in which the detection path 32 a and thehousing opening 61 are aligned and the direction in which themeasurement flow channel 32 and the sensor SA 50 are aligned.

The detection path 32 a is disposed closer to the housing base end sidethan the introduction path 32 b and the discharge path 32 c, andconnects the downstream end portion of the introduction path 32 b andthe upstream end portion of the discharge path 32 c with each other in astate where the detection path 32 a is extended to the introduction path32 b and the discharge path 32 c. The introduction path 32 b is disposeddownstream of the discharge path 32 c in the depth direction Z, and theintake air flows in the detection path 32 a in a direction opposite tothe intake passage 12 and the passage flow channel 31. In themeasurement flow channel 32, the intake air flowing in from the passageflow channel 31 once flows toward the housing base end side, and thenU-turns by passing through the detection path 32 a to flow toward thehousing tip side. With the provision of the U-turned shaped flowchannel, even if foreign matter such as dust, dust, waterdrops, or oildroplets fly off together with the intake air, the foreign matter can beprevented from damaging the detection element 22 b without reaching theflow rate detector 22, and the foreign matter can be prevented fromaccumulating to deteriorate the detection accuracy. In the first place,the foreign matter that has entered the passage flow channel 31 from theinflow port 33 a travels along the flow of the intake air, so that theforeign matter is likely to be discharged from the outflow port 33 b,and hardly flows from the passage flow channel 31 into the measurementflow channel 32. This also makes it difficult for the foreign matter toreach the flow rate detector 22.

The measurement outlet 33 c opens the discharge path 32 c in the widthdirection X. A sum total of the opening areas of the two measurementoutlets 33 c is substantially the same as the flow channel area of thedischarge path 32 c. For example, unlike the present embodiment, in aconfiguration in which the sum total of the opening areas of the twomeasurement outlets 33 c is larger than the flow channel area of thedischarge path 32 c, there is a concern that foreign matter is likely toenter the discharge path 32 c from the measurement outlet 33 c. Inaddition, in the configuration in which the sum total opening area issmaller than the flow channel area, the intake air flowing through themeasurement flow channel 32 is less likely to flow out from themeasurement outlet 33 c, and there is a concern that a flow velocity ofthe intake air passing through the flow rate detector 22 is lowered andthe detection accuracy of the flow rate detector 22 is lowered. On theother hand, according to the present embodiment, since the sum totalopening area is substantially the same as the flow channel area, anentry of foreign matter from the measurement outlet 33 c and a decreasein the flow velocity in the measurement flow channel 32 can beinhibited.

The flow rate detector 22 includes a detection board 22 a as a circuitboard, and a detection element 22 b mounted on the detection board 22 a.The detection board 22 a forms an outer contour of the flow ratedetector 22, and the detection element 22 b is disposed at the center ofthe board surface of the detection board 22 a. In that case, thedetection element 22 b is disposed at the center of the flow ratedetector 22. The detection board 22 a is electrically connected to theconnector terminals 28 a (refer to FIG. 18). The detection element 22 bhas a heat generation portion such as a heat generating resistiveelement and a temperature detector, and the flow rate detector 22outputs a detection signal according to a change in temperature causedby heat generation in the detection element 22 b. The flow rate detector22 may also be referred to as a sensor chip.

In this example, in order to properly maintain the detection accuracy ofthe flow rate detector 22, there is a need to increase a temperaturechange in the temperature detector attributable to the intake flow ratein the detection element 22 b to some extent, and in order to increasethe temperature change, it is preferable to increase a flow velocity ofa fluid coming in contact with the detection element 22 b to someextent. This is to eliminate the influence of the temperature changeacting on the detection element 22 b by natural convection with respectto the temperature change of the detection element 22 b according to theflow velocity of the fluid. The temperature change due to the naturalconvection depends on an installation angle of the detection element 22b, and causes an error in the detection signal of the temperature changedue to the fluid. With an increase in the flow velocity of the fluidcoming in contact with the detection element 22 b, the influence ofnatural convection caused by the installation angle of the detectionelement 22 b and the air flow meter 14 can be eliminated, and thedetection of the fluid can be properly maintained.

The flow rate detector 22 corresponds to a physical quantity detectorthat detects the flow rate of the intake air as a physical quantity. Theflow rate detector 22 is not limited to a thermal type flow rate sensor,and may be an ultrasonic type flow rate sensor, a Kalman vortex typeflow rate sensor, or the like.

The air flow meter 14 has a sensor sub-assembly including a tip-typeflow rate detector 22, and the sensor sub-assembly is referred to as asensor SA 50. In this instance, the sensor SA 50 may be referred to as asensor unit, and the air flow meter 14 may be referred to as a tip-typeflow rate measurement device. The sensor SA 50 corresponds to adetection unit.

As shown in FIG. 10, the sensor SA 50 includes a circuit accommodationportion 51, a junction portion 52, a sensing portion 53, and leadterminals 54, and is formed in a plate shape extending in the depthdirection Z and the height direction Y as a whole. In the heightdirection Y, the junction portion 52 is provided between the circuitaccommodation portion 51 and the sensing portion 53, and the leadterminals 54 have conductivity and extend from the circuit accommodationportion 51 toward the opposite side of the sensing portion 53. In boththe width direction X and the depth direction Z, the junction portion 52is thinner than the circuit accommodation portion 51, and the sensingportion 53 is further thinner than the junction portion 52.Specifically, in both the width dimension in the width direction X andthe depth dimension in the depth direction Z, the junction portion 52 issmaller than the circuit accommodation portion 51, and the sensingportion 53 is further smaller than the junction portion 52. In thatcase, a circuit step surface 55 is formed between the circuitaccommodation portion 51 and the junction portion 52, and a sensing stepsurface 56 is formed between the junction portion 52 and the sensingportion 53. Each of the step surfaces 55 and 56 extends annularly alonga peripheral portion of the junction portion 52 so as to becircumferentially arranged, and faces a tip side of the sensor SA 50.

The sensing portion 53 includes at least a part of the detection board22 a and the detection element 22 b in the flow rate detector 22, andalso includes a sensing support portion 57 for supporting the includedpart in the sensing portion 53. The sensing support portion 57 forms anouter contour of the sensing portion 53, and extends from the junctionportion 52 toward the tip side of the flow rate detector 22.

As shown in FIG. 8, FIG. 11, and FIG. 12, in the housing 21, the sensorSA 50 is disposed at a position where the sensing portion 53 enters thedetection path 32 a. The sensing portion 53 is disposed at anintermediate position of the detection path 32 a in the width directionX, and extends in the depth direction Z and the height direction Y. Thesensing portion 53 is in a state in which an intermediate region of thedetection path 32 a is partitioned in the width direction X, and adetection throttle portion 59 for throttling the detection path 32 a byreducing the flow channel area of the detection path 32 a is provided ata position facing the flow rate detector 22 on an inner peripheralsurface of the detection path 32 a. The detection throttle portion 59protrudes from the inner peripheral surface of the detection path 32 atoward the flow rate detector 22, and a depth dimension D1 of thedetection throttle portion 59 in the depth direction Z is larger than adepth dimension D2 of the flow rate detector 22 in the depth directionZ. In a region where the flow rate detector 22 exists in the heightdirection Y, a depth dimension D3 of the sensing support portion 57 inthe depth direction Z is larger than a depth dimension D1 of thedetection throttle portion 59.

The detection throttle portion 59 has a tapered shape in the widthdirection X. Specifically, a base end portion of the detection throttleportion 59 protruding from the inner wall of the housing body 24 in thewidth direction X is the widest portion, and a tip portion of thedetection throttle portion 59 is the narrowest portion. The widthdimension of the base end portion of the detection throttle portion 59is set to the depth dimension D1 described above. The detection throttleportion 59 has a curved surface that expands toward the flow ratedetector 22. The detection throttle portion 59 may have a tapered shapeexpanded toward the flow rate detector 22.

When a surface of the inner peripheral surface of the detection path 32a on the housing tip side is referred to as a bottom surface and asurface on the housing base end side is referred to as a ceilingsurface, the bottom surface of the detection path 32 a is formed by thehousing body 24, while the ceiling surface is formed by the sensing stepsurface 56 of the sensor SA 50. In other words, the detection path 32 ais partitioned by the sensing step surface 56. In this example, in anopen region PB, the junction portion 52 is accommodated in anaccommodation region PB1 as a part of the sensor SA 50, and a boundarybetween the accommodation region PB1 and a measurement region PB2coincides with the sensing step surface 56. When a gap exists betweenthe junction portion 52 and the housing body 24, the gap may communicatewith the detection path 32 a.

The detection throttle portion 59 extends from the bottom surface of thedetection path 32 a toward the ceiling surface. The outer peripheralsurface of the detection throttle portion 59 extends straight in theheight direction Y. In the height direction Y, the detection throttleportion 59 and the sensing step surface 56 of the sensor SA 50 areseparated from each other, and a space between the tip of the detectionthrottle portion 59 and the sensing step surface 56 is also included inthe detection path 32 a.

In the detection path 32 a, a separation distance between the sensingsupport portion 57 and the detection throttle portion 59 graduallydecreases toward the flow rate detector 22 in the depth direction Z. Inthe above configuration, when the intake air flowing into the detectionpath 32 a from the introduction path 32 b passes between the sensingsupport portion 57 and the detection throttle portion 59, the flowvelocity of the intake air is likely to increase toward the detectionelement 22 b of the flow rate detector 22. In that case, since theintake air is applied to the detection element 22 b at an appropriateflow velocity, the detection accuracy of the flow rate detector 22 canbe enhanced.

Returning to the description of FIG. 8, the housing body 24 is formed ina cylindrical shape as a whole. The housing body 24 has a housingopening 61 that opens the internal space 24 a, and the housing opening61 is formed in one end face of the housing body 24. The other end ofthe housing body 24 is closed, and the closed part is referred to as ahousing bottom portion 62, and the housing bottom portion 62 forms abottom surface of the passage flow channel 31. The housing body 24 hasholes that define the inflow port 33 a and the outflow port 33 b, andthose holes extend from the housing bottom portion 62 toward the housingbase end side.

The air flow meter 14 has a potting portion 65 as a closing portion forclosing the housing opening 61. The potting portion 65 seals theinternal space 24 a of the housing body 24 by filling the internal space24 a with a resin material such as a molten potting resin. In that case,the potting portion 65 may be referred to as a sealing portion or a sealportion. The potting portion 65 is not formed integrally with thehousing 21 in the air flow meter 14, but is formed independently of thehousing 21.

The internal space 24 a includes the sealing region PA sealed by thepotting portion 65 and the open region PB not sealed by the pottingportion 65. The sealing region PA extends from the housing opening 61toward the housing tip side, and the open region PB is disposed on thehousing tip side of the sealing region PA. The open region PB extendsfrom the sealing region PA toward the housing tip side, and the openregion PB includes the measurement flow channel 32. The boundary betweenthe sealing region PA and the open region PB extends in a directionorthogonal to the height direction Y. The sealing region PA correspondsto a potting region.

The open region PB has an accommodation region PB1 in which a part ofthe sensor SA 50 is accommodated, and a measurement region PB2 in whichthe measurement flow channel 32 is provided. The accommodation regionPB1 extends from the sealing region PA toward the housing tip side, andthe measurement region PB2 is provided on the housing tip side of theaccommodation region PB1. The boundary between the accommodation regionPB1 and the measurement region PB2 extends in a direction perpendicularto the height direction Y, and the accommodation region PB1 and themeasurement region PB2 divide the open region PB into two in the heightdirection Y.

A region step surface 66 is formed on the inner peripheral surface ofthe housing body 24 between the inner peripheral surface of the sealingregion PA and the inner peripheral surface of the open region PB. Theregion step surface 66 extends annularly so as to surround the internalspace 24 a, and faces the housing base end side. For the purpose ofreducing a wall thickness of the housing body 24 as much as possible,the housing body 24 is provided with an overhanging portion 66 a whichoverhangs to the outer peripheral side in accordance with the regionstep surface 66. The region step surface 66 and the overhanging portion66 a are disposed closer to the housing tip side than the ring holdingportion 25. The region step surface 66 corresponds to a hooking portion.

A sealing step surface 67 provided closer to the housing base end sidethan the region step surface 66 is provided on the inner peripheralsurface of the sealing region PA. Similar to the region step surface 66,the sealing step surface 67 extends annularly around the periphery ofthe sealing region PA so as to face the housing base end side.

The sensor SA 50 extends over the sealing region PA and the open regionPB in the height direction Y, and is entirely accommodated in theinternal space 24 a of the housing 21. The circuit step surface 55 ofthe sensor SA 50 is caught by the region step surface 66 of the housing21, thereby restricting the sensor SA 50 from further entering theinternal space 24 a. Further, the circuit step surface 55 and the regionstep surface 66 abut against each other in close contact with eachother, and when the potting portion 65 is formed, entering of the moltenresin into the open region PB is restricted by the abutment portion. Inthat instance, the boundary between the sealing region PA and the openregion PB coincides with the boundary between the circuit accommodationportion 51 and the junction portion 52 of the sensor SA 50. The sensorSA 50 is assembled to the housing 21, so that all or part of theinternal space 24 a of the housing 21 is occupied by the sensor SA 50.

In the depth direction Z, a depth dimension D5 of the sealing region PAat the region step surface 66 is larger than a depth dimension D6 of theopen region PB. In that instance, in the sensor SA 50, a depth dimensionD7 of the circuit accommodation portion 51 at the circuit step surface55 is smaller than the depth dimension D5 of the sealing region PA andlarger than the depth dimension D6 of the open region PB. As shown inFIG. 11, a width dimension W1 of the sealing region PA at the regionstep surface 66 in the width direction X is larger than a widthdimension W2 of the open region PB. In that instance, in the sensor SA50, a width dimension W3 of the circuit accommodation portion 51 at thecircuit step surface 55 is smaller than the width dimension W1 of thesealing region PA and larger than the width dimension W2 of the openregion PB. In this manner, a configuration is realized in which thecircuit step surface 55 of the sensor SA 50 is caught by the region stepsurface 66 of the housing 21.

In the sensor SA 50, the width direction X and the depth direction Z areorthogonal to a direction in which the circuit accommodation portion 51and the flow rate detector 22 are aligned, and orthogonal to a directionin which the sensing support portion 57 protrudes from the junctionportion 52. The width direction X and the depth direction Z are adirection orthogonal to the direction in which the lead terminals 54protrude from the circuit accommodation portion 51. In the housing 21,the depth direction Z is a direction in which the intake air flows inthe passage flow channel 31 and the detection path 32 a.

The housing body 24 has a lateral partition wall 68 and a longitudinalpartition wall 69, and the partition walls 68 and 69 are provided in alateral direction in the depth direction Z. The lateral partition wall68 divides the internal space 24 a in a direction orthogonal to theheight direction Y, thereby defining an end portion of the open regionPB on the housing tip side. The lateral partition wall 68 extends fromthe upstream-side outer peripheral portion of the housing body 24 towardthe downstream side, and separates the open region PB and the inflowpassage 31 a vertically. The lateral partition wall 68 is disposedcloser to the housing base end side than the inflow port 33 a, and formsa ceiling surface of the inflow passage 31 a. The longitudinal partitionwall 69 extends from the lateral partition wall 68 toward the housingbase end side, separates the introduction path 32 b and the dischargepath 32 c of the measurement flow channel 32 from each other, and formsthe floor surface of the detection path 32 a. The lateral partition wall68 may be referred to as a lateral partition portion, and thelongitudinal partition wall 69 may be referred to as a longitudinalpartition portion. The lateral partition wall 68 corresponds to apassage partition portion, and the longitudinal partition wall 69corresponds to a measurement partition portion.

The housing body 24 is configured not to narrow the internal space 24 aeven when the housing body 24 approaches the housing opening 61 from thehousing base end side with respect to the inflow port 33 a and theoutflow port 33 b. In the above configuration, even if the innerperipheral surface of the housing body 24 has a step surface facing thehousing base end side like the region step surface 66, there is no stepsurface facing the housing tip side. Further, a separation distancebetween portions of the inner peripheral surface of the housing 21facing each other across the internal space 24 a does not become smalleven if the separation distance increases or does not change toward thehousing opening 61 in the height direction Y.

The longitudinal partition wall 69 is configured so as not to becomethick even when approaching the housing opening 61 in the heightdirection Y. In the above configuration, a depth dimension of thelongitudinal partition wall 69 in the depth direction Z does notincrease even if the depth dimension decreases or does not change towardthe housing opening 61 in the height direction Y. In FIGS. 12 and 13,the depth dimension D1 of the detection throttle portion 59 is the sameas or smaller than a depth dimension D8 of a portion where thelongitudinal partition wall 69 is thin in the depth direction Z. As aresult, a step surface facing the housing tip side is not formed at theboundary between the detection throttle portion 59 and the longitudinalpartition wall 69.

Returning to the description of FIG. 8, the internal space 24 a of thehousing body 24 may be narrowed as the internal space 24 a approachesthe housing opening 61 in the region closer to the housing tip side thanthe lateral partition wall 68 in the height direction Y. In other words,the width dimension of the passage flow channel 31 in the widthdirection X may gradually decrease as the passage flow channel 31approaches the housing opening 61 in the height direction Y. Inaddition, a step surface facing the housing tip side may be formed onthe inner peripheral surface of the passage flow channel 31.

However, as described above, the passage flow channel 31 is configurednot to be narrowed even when approaching the inflow port 33 a in thedepth direction Z. In the above configuration, the inner peripheralsurface of the passage flow channel 31 may have a step surface facingthe inflow port 33 a side, but there is no step surface facing theoutflow port 33 b side.

In the internal space 24 a of the housing body 24, since the junctionportion 52 of the sensor SA 50 is fitted to the inner peripheral surfaceof the housing body 24, the circuit step surface 55 of the sensor SA 50and the region step surface 66 of the housing body 24 are held in anabutment position. When one surface of the plate surfaces of the sensorSA 50 on which the flow rate detector 22 is provided is referred to as afront surface and the other surface on the other side of the frontsurface is referred to as a back surface, as shown in FIGS. 8 and 14,the sensor SA 50 has a front SA protrusion 71 a protruding to the frontside and a back SA protrusion 71 b protruding to the back side. Twofront SA protrusions 71 a and two back SA protrusions 71 b are providedin each of the junction portions 52.

The housing body 24 has a width housing protrusion 72 a protruding inthe width direction X from an inner peripheral surface of the housingbody 24, and a depth housing protrusion 72 b protruding in the depthdirection Z. The housing protrusions 72 a and 72 b protrude from theinner peripheral surface of the housing body 24 toward the innerperipheral side. Two width housing protrusions 72 a are provided atpositions facing the front surface of the sensor SA 50. One depthhousing protrusion 72 b is provided at a position facing a side surfaceof the sensor SA 50 in the upstream-side outer peripheral portion of thehousing body 24, and extends in a direction away from the curved surface45 of the housing body 24 in a direction inclined with respect to thedepth direction Z.

The housing protrusions 72 a and 72 b are disposed on the innerperipheral surface of the open region PB, and thus are provided closerto the housing tip side than the ring holding portion 25. In thisexample, in the housing 21, the wall thickness of the portion where thering holding portion 25 is formed is relatively large due to theprovision of the ring holding portion 25 on the outer peripheral side ofthe housing body 24, the provision of the holding groove 25 a, and thelike. For that reason, in the case of molding the housing 21 with resin,there is a concern that the resin distortion of the portion of thehousing 21 where the ring holding portion 25 is formed is likely tooccur as the molten resin is cured. On the other hand, as describedabove, since the housing protrusions 72 a and 72 b are disposed atpositions separated from the ring holding portion 25 toward the housingtip side, the influence of the resin distortion in the ring holdingportion 25 is less likely to be applied to the housing protrusions 72 aand 72 b. For that reason, the dimensions and positions of the housingprotrusions 72 a and 72 b can be accurately realized as designed.

The respective tip end faces of the front SA protrusion 71 a and thewidth housing protrusion 72 a are in contact with each other, and theback SA protrusion 71 b is in contact with a flat portion of the innerperipheral surface of the housing body 24. As a result, the relativemovement of the sensor SA 50 to the housing body 24 in the widthdirection X is regulated. Further, in the junction portion 52, the tipend face of the depth housing protrusion 72 b abuts on the side end faceof the housing body 24 on the side of the curved surface 45, and in thejunction portion 52, the side end face of the side opposite to thecurved surface 45 abuts on the flat portion of the inner peripheralsurface of the housing body 24. As a result, the sensor SA 50 isrestricted from moving relative to the housing body 24 in the depthdirection Z.

The sensor SA 50 is disposed at a position closer to the side of theinner peripheral surface of the housing body 24 facing away from thewidth housing protrusion 72 a than the center of the internal space 24 ain the width direction X because no protrusion corresponding to the backSA protrusion 71 b is provided on the inner peripheral surface of thehousing body 24. In other words, the sensor SA 50 is disposed at aposition closer to the back surface of the sensor SA 50.

In this example, the housing protrusions 72 a and 72 b in which thesensor SA 50 is not fitted to the inner peripheral surface of thehousing body 24 at the time of manufacturing the air flow meter 14 willbe described referring to FIGS. 15 and 16. As shown in FIG. 15, theprotrusion dimensions of the housing protrusions 72 a and 72 b from theinner peripheral surface of the housing body 24 are larger than thoseafter the sensor SA 50 has been fitted. For example, the housingprotrusions 72 a and 72 b, which are not fitted with the sensor SA 50,are tapered in the protruding directions, and the housing protrusions 72a and 72 b have sharp tips.

The inner peripheral surface of the housing body 24 has a protrusionsupport surface 73 for supporting the housing protrusions 72 a and 72 b.In this example, in order to prevent the end faces of the housingprotrusions 72 a and 72 b from becoming step surfaces facing the housingtip side, a protrusion covering surface 74 for covering the housingprotrusions 72 a and 72 b from the housing tip side is included in theinner peripheral surface of the housing body 24. The protrusion coveringsurface 74 is provided closer to the housing tip side than theprotrusion support surface 73, and is disposed closer to the innerperipheral side in the width direction X and the depth direction Z thanthe protrusion support surface 73. A covering step surface 75 facing thehousing base end side is formed at a boundary between the protrusionsupport surface 73 and the protrusion covering surface 74.

As shown in FIG. 14 and FIG. 16, unlike the housing protrusions 72 a and72 b, the SA protrusions 71 a and 71 b of the sensor SA 50 have nosignificant change in shapes and dimensions before and after the SAprotrusions 71 a and 71 b are fitted to the inner peripheral surface ofthe housing body 24. This is because the SA protrusions 71 a and 71 bare made of a material having higher hardness and strength than thehousing protrusions 72 a and 72 b.

In FIGS. 15 and 16, in the housing body 24 prior to the sensor SA 50being fitted, an effective dimension W4 of the internal space 24 a inthe width direction X excluding the SA protrusions 71 a and 71 b issmaller than a width dimension W5 of the thickest part of the sensor SA50 in the width direction X. The width dimension W5 is a separationdistance between the tips of the SA protrusions 71 a and 71 b. In thatcase, when the sensor SA 50 is inserted into the internal space 24 afrom the housing opening 61, the tip portion of the width housingprotrusion 72 a is scraped off by the front SA protrusion 71 a, and thetip portion of the depth housing protrusion 72 b is scraped off by theside end face of the junction portion 52. In this instance, the sensorSA 50 is pressed toward the back surface of the inner peripheral surfaceof the housing body 24 and toward the side of the inner peripheralsurface of the housing body 24 facing away from the curved surface 45,so that the sensor SA 50 is accurately positioned in the internal space24 a in the width direction X. When the sensor SA 50 is inserted intothe internal space 24 a, the deformation of the housing protrusions 72 aand 72 b pressed by the front SA protrusion 71 a and the junctionportion 52 is more likely to occur than scraping of the tip portions ofthe housing protrusions 72 a and 72 b. In that case, the housingprotrusions 72 a and 72 b are deformed so as to be crushed by the frontSA protrusions 71 a and the junction portion 52, whereby the protrusiondimensions of the housing protrusions 72 a and 72 b are reduced.

As described above, in the configuration in which the width dimension W5of the sensor SA 50 is defined by the SA protrusions 71 a and 71 b, themanufacturing variation of the width dimension W5 is less likely tooccur as compared with the configuration in which the width dimension W5is defined by the front surface and the back surface of the junctionportion 52, for example. For that reason, the positioning accuracy ofthe sensor SA 50 with respect to the housing body 24 in the widthdirection X and the depth direction Z can be further improved ascompared with a configuration in which the sensor SA 50 does not havethe SA protrusions 71 a and 71 b.

Each of the SA protrusions 71 a and 71 b and the housing protrusions 72a and 72 b has an elongated shape extending in the height direction Y.The SA protrusions 71 a and 71 b extend from the circuit step surface 55toward the housing tip side to an intermediate position of the junctionportion 52, and the housing protrusions 72 a and 72 b extend from theregion step surface 66 toward the housing tip side to an intermediateposition of the housing body 24. In the present embodiment, the housingprotrusions 72 a and 72 b extend toward the housing tip side more thanthe SA protrusions 71 a and 71 b, and the tip portion of the widthhousing protrusion 72 a remains at the housing tip side more than thefront SA protrusion 71 a without being scraped off. When the widthhousing protrusion 72 a is deformed by being pressed by the front SAprotrusion 71 a, a portion of the width housing protrusion 72 a locatedcloser to the housing tip side than the front SA protrusion 71 a is notdeformed or slightly deformed.

The SA protrusions 71 a and 71 b may extend to the end portion of thejunction portion 52 on the housing tip side. The housing protrusions 72a and 72 b may extend to the end portion of the open region PB on thehousing tip side. In that case, since the end faces of the housingprotrusions 72 a and 72 b do not face the housing base end side in theopen region PB, there is no need to provide the protrusion coveringsurface 74 and the covering step surface 75.

FIGS. 12 and 13 are different from FIGS. 14 and 15 in thecross-sectional shape of the internal space 24 a of the housing body 24because FIGS. 12 and 13 are schematic diagrams, and FIGS. 12 to 15 arediagrams relating to the air flow meter 14 of FIG. 8. In FIG. 11, the SAprotrusions 71 a and 71 b and the housing protrusions 72 a and 72 b arenot shown, and in FIG. 14, the protrusion covering surface 74 and thecovering step surface 75 are not shown.

As shown in FIG. 17, the sensor SA 50 includes a circuit chip 81 forperforming various processes, a lead frame 82 for supporting the circuitchip 81, a relay board 83, and bonding wires 84 in addition to the flowrate detector 22 and the lead terminals 54. The relay board 83 relaysthe signal from the flow rate detector 22 to the circuit chip 81. Themultiple bonding wires 84 are provided so that the detection board 22 aand the lead terminals 54 are electrically connected to each other.

The sensor SA 50 also includes a mold portion 76 that forms an outercontour of the sensor SA 50. The mold portion 76 is made of a resinmaterial such as a mold resin, and fixes the flow rate detector 22, thelead terminals 54, the circuit chip 81, the lead frame 82, the relayboard 83, the bonding wires 84, and the like in a protected state. Thebonding wires 84 bridged between the relay board 83 and the detectionboard 22 a is protected by a protective portion 77 made of a resinmaterial such as a potting resin. The detection board 22 a is providedwith a dam material 78 extending along the peripheral portion of theprotective portion 77, and the dam material 78 serves to define theshape of the molten resin when forming the protective portion 77.

The mold portion 76 has a support surface 76 a for supporting thedetection board 22 a. The plate surface of the detection board 22 a isbonded to the support surface 76 a in an overlapping state, and thedetection board 22 a is supported in a state of being sandwiched betweenthe support surface 76 a and the protective portion 77. In this example,in the sensor SA 50, the support surface 76 a and the circuit chip 81are disposed at positions as far as possible apart from the circuit stepsurface 55 which is a fixed part with the housing body 24. For example,the support surface 76 a and the circuit chip 81 are not disposed atpositions that extend laterally to the circuit step surface 55 in thewidth direction X and the height direction Y. In this instance, even ifthe sensor SA 50 is deformed by an external force applied to the circuitstep surface 55, the flow rate detector 22 and the circuit chip 81 areless likely to be deformed, and therefore, the operation accuracy of thecircuit chip 50 can be appropriately maintained.

As shown in FIGS. 18 and 19, the lead terminals 54 of the sensor SA 50are electrically connected to the connector terminals 28 a of theconnector portion 28 through the terminal unit 85 in the sealing regionPA of the housing body 24. The multiple lead terminals 54 and themultiple connector terminals 28 a are aligned at predetermined intervalsin the depth direction Z. The lead terminal 54 and the connectorterminal 28 a corresponding to each other are disposed as a pair ofterminals at positions facing each other in the width direction X, andthose terminals 28 a and 54 are connected to each other through theterminal unit 85.

As shown in FIG. 20, the terminal unit 85 includes multiple bridgeterminals 86 and a terminal fixing portion 87 for fixing the bridgeterminals 86. Each of the bridge terminals 86 is an elongated memberhaving conductivity and extending generally in a U-shape. The bridgeterminal 86 has a first connection portion 86 a to which the connectorterminal 28 a is connected, and a second connection portion 86 b towhich the lead terminal 54 is connected. The connection portions 86 aand 86 b are portions in which parts of the bridge terminals 86 protrudewhile being curved in the thickness direction, and the protrudingportions are connected to the terminals 28 a and 54 by welding or thelike. The multiple bridge terminals 86 are aligned at predeterminedintervals in the depth direction Z, and the terminal fixing portion 87connects intermediate portions of the bridge terminals 86 to each otherin a state of extending in the depth direction Z. The terminal fixingportion 87 is formed of a resin material or the like having electricalinsulating properties.

The connector terminals 28 a, the lead terminals 54, and the bridgeterminals 86 are connected to each other and extend in the heightdirection Y. In that case, since there is no need to perform a bendingprocess such as a post-bending process in accordance with an actualpositional relationship when those terminals 28 a, 54, and 86 areconnected to each other, a work load when manufacturing the air flowmeter 14 can be reduced. Further, when the terminals 28 a, 54, and 86are connected by spot welding, the electrodes of a welding jig and theterminals 28 a, 54, and 86 can be stably brought into contact with eachother, so that a welding strength can be likely to be increased. As thewelding for connecting the terminals 28 a, 54, and 86, laser welding orthe like may be used in addition to the spot welding. The terminals 28a, 54, and 86 may be electrically connected to each other by wirebonding, soldering, or the like.

The terminal unit 85 is fixed to the housing body 24 by the terminalfixing portion 87 being caught by the sealing step surface 67 or thelike. In that case, the terminal unit 85 is positioned with respect tothe housing body 24 in the height direction Y by the sealing stepsurface 67.

In FIG. 18, the housing body 24 is not shown, and the housing opening 61and the potting portion 65 are indicated in virtual lines. In FIG. 19,the housing body 24 is illustrated, but the potting portion 65 is notillustrated. Each of the bridge terminals 86 may have a fit portion forfitting the connector terminal 28 a and the lead terminal 54. In theabove configuration, there is no need to perform spot welding on theterminals 28 a, 54, and 86.

A signal from the temperature sensing element 23 a is output from theconnector portion 28 in the order of the intake air temperatureterminals 23 c, the bridge terminals 86, the lead terminals 54, thecircuit chip 81, the lead terminals 54, the bridge terminals 86, and theconnector terminals 28 a.

In the sensor SA 50, a flow rate signal corresponding to the flow rateof the intake air flowing through the measurement flow channel 32 isoutput from the flow rate detector 22 to the circuit chip 81, and theflow rate signal is processed by the circuit chip 81 to calculate theflow rate of the intake air in the intake passage 12. The flow ratecalculated by the circuit chip 81 is transmitted to the ECU 20 bytransmitting a signal through the lead terminals 54 and the connectorterminals 28 a. As described above, the air flow meter 14 detects theflow rate of the intake air flowing through the intake passage 12 by theflow rate detector 22.

As described above, in the sealing region PA, the terminals 28 a, 54,and 86 are sealed by the potting portion 65 so as not to be exposed. Asshown in FIGS. 8 and 21, the housing body 24 has a lip 89 extendingalong the peripheral portion of the housing opening 61. The lip 89circumferentially surrounds the housing opening 61 in an annular shape,and has a function of regulating the molten resin from flowing out ofthe housing opening 61 when the potting portion 65 is formed. In thehousing 21, the flange portion 27 exists on an outer peripheral side ofthe lip 89.

As shown in FIG. 21, a surface of the potting portion 65 is located at aposition separated from the housing opening 61 toward the housing tipside in the height direction Y. The surface does not extend straight inthe width direction X and the depth direction Z, but is disposed at aposition closer to the housing opening 61 as the surface of the pottingportion 65 is closer to the inner peripheral surface of the housing body24. This is because a phenomenon occurs in which the molten resin filledin the sealing region PA creeps up the inner peripheral surface of thehousing body 24 when the potting portion 65 is formed. The creep-upphenomenon of the molten resin tends to occur particularly at cornerportions. On the other hand, in the present embodiment, as shown in FIG.3, since the housing opening 61 and the four corners of the sealingregion PA are curved surfaces, a phenomenon that the molten resin creepsup is less likely to occur, as a result of which, the molten resin isless likely to flows out of the housing opening 61. In that case, voidsand gaps are also less likely to occur when the sealing region PA isfilled with the molten resin.

When an epoxy resin is selected as a thermosetting resin used to formthe potting portion 65, an epoxy resin is harder than a urethane resin,for example, so that the positioning accuracy of the sensor SA 50 can beenhanced. As the thermosetting resin capable of forming the pottingportion 65, in addition to the epoxy resin, the urethane resin, asilicone resin, or the like can be used.

Next, a mold device 90 for molding the housing 21 with resin will bedescribed with reference to FIGS. 22 to 26. As shown in FIG. 22, themold device 90 has an inner peripheral mold portion 91 for molding theinner peripheral surface of the housing body 24, outer peripheral moldportions 102 and 103 for molding the outer peripheral surface of thehousing 21, a passage mold portion 104 for molding the passage flowchannel 31, and root mold portions 105 and 106 for molding the rootportion 29 a.

The inner peripheral mold portion 91 has a mold main body portion 92 andan inward portion 93. The mold main body portion 92 has a main bodyrecess portion 92 a for forming the outer peripheral surface of theflange portion 27 and the connector portion 28, and the inward portion93 extends from a bottom surface of the main body recess portion 92 a inorder to define the internal space 24 a of the housing body 24. When thedirection defined for the air flow meter 14 is also applied to the molddevice 90, the main body recess portion 92 a is recessed in the heightdirection Y, and the inward portion 93 extends in the height directionY. A surface of the inner peripheral surface of the main body recessportion 92 a facing in the height direction Y is referred to as a bottomsurface.

The inward portion 93 has a sealing molding portion 94 for defining thesealing region PA and an open molding portion 95 for defining the openregion PB, and the open molding portion 95 extends from the sealingmolding portion 94 in the height direction Y. The open molding portion95 has an accommodation molding portion 96 for defining theaccommodation region PB1 and a measurement molding portion 97 fordefining the measurement region PB2, and the measurement molding portion97 extends from the accommodation molding portion 96 in the heightdirection Y.

In FIGS. 22 to 24, the measurement molding portion 97 has a detectionmolding portion 97 a for defining the detection path 32 a, anintroduction molding portion 97 b for defining the introduction path 32b, and a discharge molding portion 97 c for defining the discharge path32 c. The introduction molding portion 97 b and the discharge moldingportion 97 c extend from the detection molding portion 97 a in theheight direction Y, and are both elongated columnar members. Theintroduction molding portion 97 b and the discharge molding portion 97 care aligned laterally in the depth direction Z in a state of beingseparated from each other, and the detection molding portion 97 aconnects the introduction molding portion 97 b and the discharge moldingportion 97 c. The introduction molding portion 97 b corresponds to anintroduction column portion, the discharge molding portion 97 ccorresponds to a discharge column portion, and the detection moldingportion 97 a corresponds to a columnar connection portion.

The inner peripheral mold portion 91 is configured so that the inwardportion 93 can be extracted from the housing opening 61 when the housing21 is molded with resin. More specifically, in the inward portion 93,the sealing molding portion 94, the accommodation molding portion 96,the detection molding portion 97 a, the introduction molding portion 97b, and the discharge molding portion 97 c may be thinned or unchangedtoward the tip portion of the inward portion 93, but are not thickened.Further, even if a step surface facing the tip side of the inwardportion 93 is formed on an outer peripheral surface of the inwardportion 93, a step surface facing a base end side of the inward portion93 is not formed. Therefore, in the inward portion 93, a width dimensionin the width direction X and a depth dimension in the depth direction Zmay be smaller or unchanged toward the tip portion of the inward portion93 but are not larger. In this example, the tip portion of the innerperipheral mold portion 91 is a side of the introduction molding portion97 b and the discharge molding portion 97 c which is not connected tothe detection molding portion 97 a.

In particular, in FIG. 23 and FIG. 24, a separation distance L1 betweenthe introduction molding portion 97 b and the discharge molding portion97 c may be larger or unchanged toward the tip portion of the inwardportion 93, but are not smaller. A separation distance L2 between theouter surfaces of the introduction molding portion 97 b and thedischarge molding portion 97 c may be smaller or unchanged toward thetip portion of the inward portion 93, but are not larger. Further, whenone way in the width direction X is referred to as a right way and theother way is referred to as a left way, a separation distance between aright surface of the outer peripheral surface of the introductionmolding portion 97 b facing rightward and a left surface of the outerperipheral surface of the discharge molding portion 97 c facing leftwarddoes not increase toward the tip portion of the inward portion 93.Similarly, a separation distance between a left surface of theintroduction molding portion 97 b and a right surface of the dischargemolding portion 97 c does not increase toward the tip portion of theinward portion 93.

The passage mold portion 104 is configured so as to be extractable fromthe inflow port 33 a when the housing 21 is molded with resin.Specifically, in FIGS. 22, 25, and 26, the passage mold portion 104 isan elongated columnar member extending in the depth direction Z. In thepassage mold portion 104, when a portion for forming the outflow port 33b is referred to as a tip portion, the passage mold portion 104 may bethinner or unchanged toward the tip portion of the passage mold portion104, but is not thicker. Further, even if a step surface facing the tipside of the passage mold portion 104 is formed on the outer peripheralsurface of the passage mold portion 104, a step surface facing the baseend side of the passage mold portion 104 is not formed. Therefore, inthe passage mold portion 104, the width dimension in the width directionX and the height dimension in the height direction Y may be smaller orunchanged toward the tip portion of the passage mold portion 104, butare not larger.

Returning to the description of FIG. 22, the pair of outer peripheralmold portions 102 and 103 are aligned side by side in the widthdirection X. The width direction X is a direction orthogonal to thedepth direction Z, which is an alignment direction of the introductionmolding portion 97 b and the discharge molding portion 97 c in the innerperipheral mold portion 91. A housing recess portion 111 for molding thehousing 21 and a mold recess portion 112 for accommodating the passagemold portion 104 and the root mold portions 105 and 106 are formed inthe pair of outer peripheral mold portions 102 and 103. In the outerperipheral surface of the flange portion 27 and the outer peripheralsurface of the connector portion 28, portions different from each otherare molded in the main body recess portion 92 a of the inner peripheralmold portion 91 and the housing recess portion 111 of the outerperipheral mold portions 102 and 103. The outer peripheral mold portions102 and 103 each have an outlet extension portion 113 for defining themeasurement outlet 33 c, and the outlet extension portion 113 extends inthe width direction X from a bottom surface of the mold recess portion112 for the housing 21. In addition, the first outer peripheral moldportion 102 has a mold portion (not shown) that enters an interior ofthe main body recess portion 92 a of the inner peripheral mold portion91 in order to form the inner peripheral surface of the connectorportion 28, and a recess portion in order to form the protectiveprotrusion 29 b.

The first outer peripheral mold portion 102 corresponds to a first moldportion, and the second outer peripheral mold portion 103 corresponds toa second mold portion. The width direction X in which the outletextension portion 113 extends is also an alignment direction of thefirst outer peripheral mold portion 102 and the second outer peripheralmold portion 103.

The pair of root mold portions 105 and 106 are aligned side by side inthe depth direction Z between the first outer peripheral mold portion102 and the second outer peripheral mold portion 103. In the root moldportions 105 and 106, recess portions for molding the root portion 29 aare provided on the respective tip end faces. The recess portion of thefirst root mold portion 105 has a shape corresponding to theupstream-side end face of the root portion 29 a, and the recess portionof the second root mold portion 106 has a shape corresponding to thedownstream-side end face of the root portion 29 a.

Next, as a method of manufacturing the air flow meter 14, a method ofmanufacturing the housing 21 with the use of the mold device 90 will bedescribed. The method of manufacturing the air flow meter 14 correspondsto a method of manufacturing the physical quantity measurement device.

First, the mold portions 91 and 102 to 106 are prepared for the molddevice 90. Then, those mold portions 91 and 102 to 106 are assembledtogether. For example, the first outer peripheral mold portion 102 andthe second outer peripheral mold portion 103 are fixed to each otherwith their respective recess portions facing each other, and the inwardportion 93 of the inner peripheral mold portion 91, the passage moldportion 104, and the root mold portions 105 and 106 are inserted intothe opening defined between the outer peripheral mold portions 102 and103. The opening is defined by the respective mold recess portions 112of the outer peripheral mold portions 102 and 103, and the inwardportion 93 of the inner peripheral mold portion 91, the passage moldportion 104, and the root mold portions 105 and 106, which have beeninserted from the opening slide inside the mold recess portion 112. Inthe above step, the second outer peripheral mold portion 103 may bemounted on the first outer peripheral mold portion 102 in a state wherethe first outer peripheral mold portion 102 is installed on a work tableor the like, and the inward portion 93 of the inner peripheral moldportion 91, the passage mold portion 104, and the two root mold portions105, 105 are mounted in the recess portion of the first outer peripheralmold portion 102. In short, the above step has only to assemble the molddevice 90.

In the assembled state of the mold device 90, the outlet extensionportions 113 of the outer peripheral mold portions 102 and 103 abutagainst the discharge molding portion 97 c of the inner peripheral moldportion 91, thereby realizing a configuration in which the measurementoutlet 33 c penetrates through the outer peripheral portion of thehousing 21. In the above state, the tip end face of the passage moldportion 104 abuts against at least one of the inner peripheral surfacesof the housing recess portions 111 of the outer peripheral mold portions102 and 103, thereby realizing a configuration in which the outflow port33 b penetrates through the outer peripheral portion of the housing 21.In addition, a configuration in which the tip portion of the passagemold portion 104 extends beyond the introduction molding portion 97 band the tip end face abuts against both of the outer peripheral moldportions 102 and 103 can be referred to as an inlay structure. With theabove inlay structure, an effect of inhibiting burrs around the outflowport 33 b can be obtained.

The intake air temperature terminals 23 c and the connector terminals 28a are preliminarily attached to the inner peripheral mold portion 91 andthe outer peripheral mold portions 102 and 103 in a state of beingconnected to each other before assembling the mold device 90. As aresult, even when the housing 21 is integrally molded, a configurationin which the terminals 23 c and 28 a are embedded in the housing 21 canbe realized.

After assembly of the mold device 90 has been completed, molten resin isinjected into the mold device 90 through only one injection portprovided in the mold device 90. The injection port is formed in, forexample, the first outer peripheral mold portion 102, and the moltenresin for integrally molding the entire housing 21 is completely filledinto the inside of the mold device 90 by one injection. Although theresin injection may be performed multiple times, all of the molten resindivided into multiple injections are used for integrally molding thehousing 21. Unlike the present embodiment, for example, when a housingis manufactured by performing resin injection for molding the multiplemembers and resin injection for joining those members to each other, itis considered that the housing is not integrally molded.

After the molten resin filled in the gaps between the mold portions 91,102 to 106 has been cured in the mold device 90, the mold portions 91,and 102 to 106 are removed from the housing body 24 by disassembling themold device 90. For example, the housing 21 is removed from the outerperipheral mold portions 102 and 103 by extracting the inward portion 93of the inner peripheral mold portion 91, the passage mold portion 104,and the root mold portions 105 and 106 from the opening between theouter peripheral mold portions 102 and 103 and separating the outerperipheral mold portions 102 and 103 from each other. After the outerperipheral mold portions 102 and 103 have been separated from eachother, the inner peripheral mold portion 91, the passage mold portion104, and the root mold portions 105 and 106 may be removed from thehousing 21. In short, the housing 21 may be removed by disassembling themold device 90.

In this example, in the inner peripheral mold portion 91, the innerperipheral surface of the housing body 24 can be integrally molded byrealizing a configuration in which the inward portion 93 can beextracted from the housing opening 61 as described above. For example,as shown in FIG. 24, the measurement flow channel 32 is integrallymolded by detaching the measurement molding portion 97 from the innerperipheral surface of the housing body 24. With respect to the passagemold portion 104, a configuration in which the passage mold portion 104can be extracted from the inflow port 33 a is realized as describedabove, with the result that the inner peripheral surface of the passageflow channel 31 can be integrally molded as shown in FIG. 26. Whenmolding the resin of the housing 21, the introduction molding portion 97b reaches the outflow passage 31 b beyond the flow channel boundaryportion 34. As a result, even if the outflow passage 31 b is inclinedtoward the housing base end side with respect to the inflow passage 31a, the passage mold portion 104 can be avoided from being caught by thelongitudinal partition wall 69 so that the passage mold portion 104cannot be extracted from the inflow port 33 a.

<Effects of Configuration Group A>

The effects of a configuration group A on integral molding of themeasurement flow channel will be described. According to the presentembodiment, since the housing 21 is integrally molded with the use ofthe mold device 90, there is no need to manufacture the housing 21 byseparately molding the multiple members with resin and then combiningthose members together. In that case, a step is less likely to occur onthe inner peripheral surface of the passage flow channel 31 or themeasurement flow channel 32 at the boundary between the members, and thewidth dimensions of the passage flow channel 31 and the measurement flowchannel 32 are less likely to vary from product to product in the widthdirection X. With a reduction in the manufacturing variation in thismanner, the detection accuracy of the intake air amount by the flow ratedetector 22 can be enhanced.

According to the present embodiment, since the outer peripheral surfaceof the housing 21 is formed using at least two mold portions, that is,the first outer peripheral mold portion 102 and the second outerperipheral mold portion 103, the degree of freedom of the outerperipheral shape of the housing 21 can be enhanced. In addition, sincethe width direction X in which the outer peripheral mold portions 102and 103 are aligned in the mold device 90 is orthogonal to the depthdirection Z in which the introduction path 32 b and the discharge path32 c are aligned, the depth dimension of the housing recess portions 111is reduced as compared with, for example, a configuration in which theouter peripheral mold portions 102 and 103 are aligned in the depthdirection Z. In that case, since the molten resin is likely to spreadover the entire housing recess portions 111, a product defect in which apart of the resin-molded housing 21 is missing can be inhibited fromoccurring.

According to the present embodiment, since the outlet extension portion113 of the first outer peripheral mold portion 102 abuts against theinner peripheral mold portion 91 in the mold device 90, the measurementoutlet 33 c penetrating through the outer peripheral portion of thehousing 21 can be molded by the mold device 90. For that reason, a workload for providing the measurement outlet 33 c can be reduced ascompared to a method in which the measurement outlet 33 c is providedby, for example, molding the housing 21 and then performing a holedrilling process on the outer peripheral portion of the housing 21. Inaddition, in order to mold the measurement outlet 33 c that penetratesthrough the outer peripheral portion of the housing 21 in the widthdirection X, the outlet extension portion 113 may be extended from thefirst outer peripheral mold portion 102 in the width direction X. Forthat reason, unlike the passage flow channel 31 molded with the use ofthe passage mold portion 104, for example, there is no need to use adedicated mold portion for molding the measurement outlet 33 cseparately from the first outer peripheral mold portion 102. In thatcase, the manufacturing cost of the mold device 90 can be reduced asmuch as the dedicated mold portion is not used, and further, the workload required for assembling the mold device 90 can be reduced by notusing the dedicated mold portion.

According to the present embodiment, in the mold device 90, since thepassage mold portion 104 is aligned with the inner peripheral moldportion 91 in the depth direction Z, a configuration in which the inflowport 33 a and the outflow port 33 b of the passage flow channel 31 areopened in the depth direction Z can be realized by resin molding. Forexample, unlike the present embodiment, in a configuration in which adedicated portion for providing the inflow port 33 a and the outflowport 33 b opened in the depth direction Z is provided in the first outerperipheral mold portion 102, it becomes difficult to remove the firstouter peripheral mold portion 102 from the housing 21 in the widthdirection X.

According to the present embodiment, the flange portion 27 and theconnector portion 28 extending from the housing body 24 in the widthdirection X and the depth direction Z are molded by combining the moldmain body portion 92 of the inner peripheral mold portion 91 and theouter peripheral mold portions 102 and 103. In order to mold the flangeportion 27 and the connector portion 28 in this manner, the mold mainbody portion 92 and the outer peripheral mold portions 102 and 103 arecombined together in the height direction Y, thereby being capable ofeasily removing the mold main body portion 92 and the outer peripheralmold portions 102 and 103 from the flange portion 27.

According to the present embodiment, in the mold device 90, the inwardportion 93 of the inner peripheral mold portion 91 is in a state ofentering the housing recess portion 111 of each of the outer peripheralmold portions 102 and 103. In this case, after the molten resin has beencured, the operator or the like can remove the inner peripheral moldportion 91 from the housing 21 by pulling out the inward portion 93 fromthe housing opening 61 in a state of holding the mold main body portion92. For that reason, the mold device 90 which realizes the integralmolding of the housing 21 can be realized, and moreover, and the molddevice 90 can be removed from the housing 21.

According to the present embodiment, in the housing 21, the internalspace 24 a is not narrowed even when the internal space 24 a comescloser to the housing opening 61 in the height direction Y. For thatreason, when the housing 21 is molded with resin by using the molddevice 90, the inward portion 93 of the inner peripheral mold portion 91can be extracted from the housing opening 61. This makes it unnecessaryto divide the portion defining the internal space 24 a in the housing 21into multiple members. For example, unlike the present embodiment, inthe housing 21 in which the internal space 24 a is narrowed toward thehousing opening 61, the inward portion 93 is caught on the innerperipheral surface of the narrowed portion, which makes it difficult toextract the inward portion 93 from the housing opening 61. In the aboveconfiguration, the portion defining the internal space 24 a is dividedinto multiple members, and those members are assembled together tomanufacture the internal space 24 a, as a result of which, themanufacturing variation as described above is likely to occur.

Moreover, if the internal space 24 a is not narrowed toward the housingbase end side, the internal space 24 a is narrowed toward the housingtip side. In the above configuration, since the measurement flow channel32 and the passage flow channel 31 are reduced in size as much aspossible relative to the sensor SA 50, the housing 21 can be downsized.In addition, when the housing 21 is downsized, the resin material usedfor manufacturing the housing 21 is reduced, so that the material costrequired for manufacturing the housing 21 can be reduced. In otherwords, the manufacturing cost of the air flow meter 14 can be reduced.

According to the present embodiment, the region step surface 66 on whichthe sensor SA 50 is caught faces the housing opening 61. For thatreason, the sensor SA 50 can be positioned by the region step surface 66in the height direction Y while the region step surface 66 realizes aconfiguration in which the internal space 24 a is not narrowed towardthe housing opening 61. Therefore, when manufacturing the air flow meter14, the operator can accurately position the sensor SA 50 by easilyinserting the sensor SA 50 into the housing opening 61 to a positionwhere the housing opening 61 is caught by the region step surface 66.

According to the present embodiment, since the circuit step surface 55of the sensor SA 50 and the region step surface 66 of the housing 21 arein contact with each other over the entire circumference of the circuitstep surface 55 and the housing 21, the sealing region PA and the openregion PB can be separated from each other by the abutment portions ofthe circuit step surface 55 and the region step surface 66. In thatcase, since the molten resin filled in the sealing region PA isrestricted from flowing into the open region PB at the time ofmanufacturing the potting portion 65, the size and shape of the openregion PB and the measurement flow channel 32 can be avoided from beingunintentionally changed by the molten resin.

According to the present embodiment, even if the longitudinal partitionwall 69 that separates the introduction path 32 b and the discharge path32 c in the open region PB is not thinner even if the longitudinalpartition wall 69 comes closer to the housing opening 61 in the heightdirection Y. For that reason, the introduction molding portion 97 b andthe discharge molding portion 97 c can be extracted from theintroduction path 32 b and the discharge path 32 c in the inward portion93 of the inner peripheral mold portion 91. This makes it possible torealize a configuration in which the inward portion 93 of the innerperipheral mold portion 91 can be extracted from the housing opening 61.

According to the present embodiment, since the detection throttleportion 59 is provided in the detection path 32 a of the measurementflow channel 32, the flow velocity of the intake air passing through theflow rate detector 22 tends to be increased, and thus the detectionaccuracy of the flow rate detector 22 can be enhanced. The detectionthrottle portion 59 does not become thick even when the detectionthrottle portion 59 comes closer to the housing opening 61 in the heightdirection Y, extends from the longitudinal partition wall 69 toward thehousing opening 61 side, and is not thicker than the longitudinalpartition wall 69. For that reason, when molding the resin of thehousing 21, the inward portion 93 of the inner peripheral mold portion91 can be removed from the longitudinal partition wall 69 and thedetection throttle portion 59.

According to the present embodiment, since the passage flow channel 31is provided closer to the housing tip side than the measurement regionPB2, a configuration can be realized in which the measurement flowchannel 32 is molded by the inward portion 93 of the inner peripheralmold portion 91 and the passage flow channel 31 is molded by the passagemold portion 104. In the above configuration, there is a need to makethe depth direction Z in which the passage mold portion 104 is extractedfrom the passage flow channel 31 orthogonal to the height direction Y inwhich the inward portion 93 is extracted from the housing opening 61.For that reason, even if the lateral partition wall 68 that separatesthe detection path 32 a and the passage flow channel 31 from each otherextends in the depth direction Z, the lateral partition wall 68 can bemolded by the passage mold portion 104 and the inward portion 93 of theinner peripheral mold portion 91. Therefore, even if the housing 21includes the lateral partition wall 68 extending in the depth directionZ, the housing 21 can be integrally molded.

Unlike the present embodiment, there is a physical quantity measurementdevice in which a measurement flow channel is defined by a combinationof multiple members. The physical quantity measurement device has a pairof covers facing each other and a main body portion provided between thecovers. In the physical quantity measurement device, a sub-passage isprovided between the cover and the main body portion or between a pairof covers, and a flow rate detector for detecting a flow rate of theintake air is provided in the sub passage. The pair of covers and themain body portion are formed independently of each other by a resinmolding process of injecting a thermoplastic resin into a mold, and areassembled together to provide sub-passage.

However, in a configuration in which the sub-passage is defined bymultiple members such as the pair of covers and the main body portion,there is a concern that the shape, size, and the like of the sub-passagemay vary from product to product due to a positional deviation betweenthose members. For example, when the position at which the pair ofcovers are attached to the main body portion deviates from each other inthe thickness direction of the housing, the flow channel area of thesub-passage varies from product to product. On the other hand, accordingto the present embodiment, the manufacturing variation of themeasurement flow channel for measuring the physical quantity can bereduced.

<Description of Configuration Group B>

A configuration group B relating to the position of the measurementoutlet will be described with reference to FIG. 27, FIG. 28, and thelike. Although FIG. 6, FIG. 7, and the like show that the thinnedportions 41 are provided on the flat surface 44 on the outer peripheralsurface of the housing 21, a description will be advanced on theassumption that the thinned portions 41 are not provided on the flatsurface 44.

As shown in FIGS. 27 and 28, in the outer peripheral surface of thehousing 21, the upstream end portion is referred to as an outerperipheral upstream end 132 a, and the downstream end portion isreferred to as an outer peripheral downstream end 132 b. In that case,the housing 21 has a curved surface 45 formed by gradually decreasingthe thickness in the width direction X from the flat surface 44 towardthe outer peripheral upstream end 132 a in the depth direction Z. Inthat case, in the housing 21, the width dimension in the width directionX gradually decreases toward the outer peripheral upstream end 132 a.

On the outer peripheral surface of the housing 21, there are boundaries131 a and 131 b between the flat surface 44 and the curved surface 45.The vertical boundary 131 a extends in the height direction Y, and thelateral boundary 131 b extends in the depth direction Z. If a surface ofouter peripheral surfaces of the housing 21 on the connector portion 28side is referred to as a front surface and a surface on the oppositeside to the front surface is referred to as a back surface, the frontsurface and the back surface are aligned in the width direction X andare a pair of side surfaces included in the outer peripheral surface ofthe housing 21. The outer peripheral upstream end 132 a is a boundarybetween the front curved surface 45 and the back curved surface 45, andextends in the height direction Y. On the other hand, the outerperipheral downstream end 132 b is a plane extending in the widthdirection X and the height direction Y. The outflow port 33 b isprovided at the outer peripheral downstream end 132 b.

On the outer peripheral surface of the housing 21, the flat surface 44,the curved surface 45, and the measurement outlet 33 c all have alongitudinally long shape extending in the height direction Y. Inparticular, the measurement outlet 33 c has a flat shape extending alongthe vertical boundary 131 a in a state of extending across the verticalboundary 131 a in the depth direction Z. In the measurement outlet 33 c,the longitudinal dimension in the height direction Y is larger than thelateral dimension in the depth direction Z. The open area of themeasurement outlet 33 c is smaller than the open area of the inflow port33 a.

In the height direction Y, a height dimension H11 of the flat surface 44is larger than both a height dimension H12 of the curved surface 45 anda height dimension H13 of the measurement outlet 33 c, and the heightdimension H12 of the curved surface 45 is larger than the heightdimension H13 of the measurement outlet 33 c. In the height direction Y,the curved surface 45 and the measurement outlet 33 c are disposed at anintermediate position of the flat surface 44, and the measurement outlet33 c is disposed at an intermediate position of the flat surface 44. Inthat case, both one end portion of the curved surface 45 on the housingtip side and the other end portion on the housing base end side areincluded in the lateral boundary 131 b.

On the outer peripheral surface of the housing 21, there is the verticalboundary 131 a between the outer peripheral upstream end 132 a and theouter peripheral downstream end 132 b, and the vertical boundary 131 ais located closer to the outer peripheral upstream end 132 a. In thatcase, in the depth direction Z, a length dimension L11 of the flatsurface 44 is larger than a length dimension L12 of the curved surface45. A length dimension L13 of the measurement outlet 33 c is smallerthan both the length dimension L11 of the flat surface 44 and the lengthdimension L12 of the curved surface 45. The depth direction Z is analignment direction of the outer peripheral upstream end 132 a and theouter peripheral downstream end 132 b, and the flat surface 44 extendsin the alignment direction. Among the directions extending along theflat surface 44, the height direction Y corresponds to a directionorthogonal to the alignment direction.

The measurement outlet 33 c is disposed at a position closer to theouter peripheral upstream end 132 a in the depth direction Z. In thatcase, a separation distance L14 between the measurement outlet 33 c andthe outer peripheral upstream end 132 a is smaller than a separationdistance L15 between the measurement outlet 33 c and the outerperipheral downstream end 132 b. In this example, when an upstream endportion of the measurement outlet 33 c is referred to as an outletupstream end 134 a, and a downstream end portion of the measurementoutlet 33 c is referred to as an outlet downstream end 134 b, a verticalboundary 131 a is located closer to the outlet upstream end 134 a in thedepth direction Z. In that case, in the depth direction Z, a separationdistance L16 between the outlet upstream end 134 a and the verticalboundary 131 a is smaller than a separation distance L17 between theoutlet downstream end 134 b and the vertical boundary 131 a.

The inner peripheral surface of the measurement flow channel 32 hasdefining surfaces 135 a to 135 c that define the measurement outlet 33c. A through hole for forming the measurement outlet 33 c is provided inthe outer peripheral portion of the housing 21, and the definingsurfaces 135 a to 135 c are included in the inner peripheral surface ofthe through hole. The upstream defining surfaces 135 a forms the outletupstream end 134 a of the measurement outlet 33 c, and is orthogonal tothe flat surface 44 because the upstream defining surface 135 a facesthe downstream side in a state of being orthogonal to the depthdirection Z. The downstream defining surface 135 b forms the outletdownstream end 134 b, and is inclined with respect to the flat surface44 by being inclined toward the upstream side in a state of beinginclined toward the outer peripheral side. A pair of the connectiondefining surfaces 135 c connect the upstream defining surface 135 a andthe downstream defining surface 135 b, and the pair of the definingsurfaces 135 a and 135 b are provided to sandwich the defining surfaces135 a and 135 b. Each connection defining surface 135 c is orthogonal tothe height direction Y.

The downstream defining surface 135 b is an inclined surface extendingstraight from the outlet downstream end 134 b toward the innerperipheral side of the housing 21, and is not orthogonal to thedownstream flat portion 137 a. The downstream defining surface 135 bprovided on each of the front side and the back side of the housing 21is a tapered surface in which the housing 21 is thinned toward theoutlet upstream end 134 a of the measurement outlet 33 c. An inclinationangle θ1 of the downstream defining surface 135 b with respect to theflat surface 44 such as the downstream flat portion 137 a is, forexample, 30 degrees. The inclination angle θ1 may be larger or smallerthan 30 degrees, but is preferably equal to or smaller than 30 degrees.

The flat surface 44 has a downstream flat portion 137 a, a tip-side flatportion 137 b, and a base end-side flat portion 137 c. The downstreamflat portion 137 a extends from the measurement outlet 33 c toward theouter peripheral downstream end 132 b in the depth direction Z. Thetip-side flat portion 137 b extends from the downstream flat portion 137a toward the housing tip side, and the base end-side flat portion 137 cextends from the downstream flat portion 137 a toward the housing baseend side. In that case, the downstream flat portion 137 a is disposedbetween the tip-side flat portion 137 b and the base end-side flatportion 137 c in the height direction Y.

The tip-side flat portion 137 b also has a portion of the measurementoutlet 33 c and the curved surface 45 which goes around the housing tipside, and the portion extends toward the housing tip side from themeasurement outlet 33 c and the curved surface 45. The base end-sideflat portion 137 c also includes a portion of the measurement outlet 33c and the curved surface 45 which goes around the housing base end side,and the portion extends toward the housing base end side from themeasurement outlet 33 c and the curved surface 45.

The degree of bending of the curved surface 45 is not uniform, and aportion having the largest degree of bending of the curved surface 45 isdisposed at a position closer to the outer peripheral upstream end 132 ain the depth direction Z. For that reason, since the measurement outlet33 c is disposed at a position extending across the vertical boundary131 a, the measurement outlet 33 c is disposed at a portion having thesmallest degree of bending which is the downstream end portion of thecurved surface 45, and when the measurement outlet 33 c is viewed fromthe upstream side, the measurement outlet 33 c appears as an elongatedshape extending in the depth direction Z. In that case, unlike thepresent embodiment, the width dimension W11 of the measurement outlet 33c in the width direction X is smaller than, for example, a configurationin which the measurement outlet 33 c is disposed at a position separatedfrom the downstream end portion of the curved surface 45 toward theouter peripheral upstream end 132 a.

The curved surface 45 has an upstream curved portion 138 a, a tip-sidecurved portion 138 b, and a base end-side curved portion 138 c. Theupstream curved portion 138 a extends from the measurement outlet 33 ctoward the outer peripheral upstream end 132 a in the depth direction Z.The tip-side curved portion 138 b extends from the upstream curvedportion 138 a toward the housing tip side, and the base end-side curvedportion 138 c extends from the upstream curved portion 138 a toward thehousing base end side. In that case, the upstream curved portion 138 ais disposed between the tip-side curved portion 138 b and the baseend-side curved portion 138 c in the height direction Y.

The tip-side curved portion 138 b has a portion of the measurementoutlet 33 c which extends around the housing tip side, and the portionenters between the measurement outlet 33 c and the tip-side flat portion137 b, and extends from the measurement outlet 33 c toward the housingtip side. The base end-side curved portion 138 c has a portion of themeasurement outlet 33 c which extends around the housing base end side,and the portion enters between the measurement outlet 33 c and the baseend-side flat portion 137 c, and extends from the measurement outlet 33c toward the housing base end side.

The flat surface 44 corresponds to an outer peripheral flat surface, andthe curved surface 45 corresponds to an outer peripheral inclinedsurface inclined with respect to the outer peripheral flat surface. Inthe flat surface 44, the tip-side flat portion 137 b and the baseend-side flat portion 137 c correspond to an extended flat portion, andin the curved surface 45, the upstream curved portion 138 a correspondsto an upstream inclined portion, and the tip-side curved portion 138 band the base end-side curved portion 138 c correspond to an extendedinclined portion. The vertical boundary 131 a corresponds to an outerperipheral boundary.

In addition, when the width direction X is referred to as a firstdirection, and the respective surfaces located on both sides of thehousing 21 in the first direction is referred to as a first surface anda second surface, the flat surface 44 and the curved surface 45 areincluded in each of the first surface and the second surface. When thedepth direction Z is referred to as a second direction, the outerperipheral upstream end 132 a is referred to as a third surface, and theouter peripheral downstream end 132 b is referred to as a fourthsurface, the third surface and the fourth surface are located on bothsides of the housing 21 in the second direction. The measurement outlet33 c is provided on each of the first surface and the second surface,and is opened toward the outside of the housing 21 so as not to face thefourth surface side in the second direction.

Next, a flow of the intake air generated on the outer peripheral side ofthe housing 21 in the intake passage 12 will be described with referenceto FIG. 28.

Of the intake air flowing forward through the intake passage 12, an airAF1 reaching the outer peripheral upstream end 132 a of the housing 21reaches the measurement outlet 33 c while changing a flow direction ofthe intake air flowing along the upstream curved portion 138 a of thecurved surface 45. In that instance, when the air AF1 reaches themeasurement outlet 33 c, the flow direction of the air AF1 is closer toan alignment direction of the outlet upstream end 134 a and the outletdownstream end 134 b, and the air AF1 is less likely to flow into themeasurement outlet 33 c. For that reason, a backflow in which the airAF1 flows into the measurement outlet 33 c is less likely to occur, andthe measurement outlet 33 c is less likely to receive a dynamic pressurefrom the air AF1 at the time of a forward flow.

Further, the air whose flow direction is gradually changed by proceedingalong the curved surface 45 is less likely to be separated from the flatsurface 44 when reaching the flat surface 44. For that reason, in theperiphery of the measurement outlet 33 c and the periphery of thevertical boundary 131 a, a turbulence of the air flow attributable tothe separation of the air flow from the flat surface 44 is less likelyto occur, and the flow of the air is more likely to be stabilized. Inthat case, since the pressure applied from the air to the measurementoutlet 33 c is likely to be stabilized, the flow of the air in themeasurement flow channel 32 is also likely to be stabilized.

The air AF2 flowing along the downstream flat portion 137 a of the flatsurface 44 travels in the depth direction Z even after passing throughthe downstream end portion of the downstream flat portion 137 a, so thatthe air is separated from the outer peripheral surface of the housing21. Along with the separation of the air AF2, the turbulence of the airflow such as a vortex is likely to occur in the periphery of the outerperipheral downstream end 132 b or the like on the downstream side ofthe downstream flat portion 137 a. Due to the turbulence of the airflow, an air AF3 that flows backward toward the outer peripheraldownstream end 132 b may occur in the vicinity of the outer peripheraldownstream end 132 b. In the present embodiment, the backflow of only apart of the air such as the air AF3 is referred to as a partialbackflow.

Unlike the present embodiment, for example, in the configuration inwhich the measurement outlet is provided at the outer peripheraldownstream end 132 b or the like downstream of the downstream flatportion 137 a, the backflow of the airflow AF3 flowing into themeasurement outlet is likely to occur. On the other hand, since themeasurement outlet 33 c of the present embodiment is not disposeddownstream of the downstream flat portion 137 a, the airflow AF3 doesnot flow into the measurement outlet 33 c.

When the entire backflow in which the intake air flows backward in theentire intake passage 12 occurs, when an air AF4 flowing backward in theintake passage 12 reaches the outer peripheral downstream end 132 b, theouter peripheral downstream end 132 b receives a dynamic pressure fromthe air AF4. For that reason, unlike the present embodiment, in theconfiguration in which the measurement outlet opened toward thedownstream side is provided at the outer peripheral downstream end 132 bor the like, the measurement outlet receives the dynamic pressure fromthe air AF4. On the other hand, since the measurement outlet 33 c of thepresent embodiment is not provided at the outer peripheral downstreamend 132 b and is not open toward the downstream side, the measurementoutlet 33 c does not receive the dynamic pressure from the air AF4. Inaddition, a backflow of the air AF4 flowing into the measurement outlet33 c does not occur.

After flowing into the inflow port 33 a, an air AF5 flowing out from themeasurement outlet 33 c through the measurement flow channel 32 flowsalong the downstream defining surface 135 b, so that the air easilyflows along the downstream flat portion 137 a after flowing out from themeasurement outlet 33 c. In that instance, after the air AF5 has flowedout from the measurement outlet 33 c, the air AF5 is less likely toseparate from the downstream flat portion 137 a, and the turbulence ofthe air flow such as a vortex flow is less likely to be generated in thevicinity of the measurement outlet 33 c with the separation of the airflow AF5 from the downstream flat portion 137 a.

Unlike the present embodiment, for example, in a configuration in whichthe downstream defining surface 135 b is orthogonal to the flat surface44 similarly to the upstream defining surface 135 a, the air AF6 flowingout from the measurement outlet 33 c proceeds in a direction orthogonalto the flat surface 44. In this example, it is considered that aturbulence of the air flow such as a vortex flow is likely to occur inthe vicinity of the measurement outlet 33 c due to, for example, a largedifference between a traveling direction of the air AF6 and a travelingdirection of the air flowing forward in the depth direction Z from theouter peripheral side of the housing 21. Further, in that instance, itcan be considered that the air AF6 flows out from the measurement outlet33 c to be separated from the downstream flat portion 137 a, and theturbulence of the air flow is likely to occur in the vicinity of themeasurement outlet 33 c in association with the separation of the air.

In the configuration group B according to the present embodiment, themeasurement outlet 33 c is not opened toward the outer peripheraldownstream end 132 b. For that reason, even if a partial backflow of theair AF3 or the like or an entire backflow of the air AF4 or the likeoccurs in the intake passage 12, the intake air is less likely to flowinto the measurement outlet 33 c in association with the backflow. Inthat case, since the flow of the intake air in the measurement flowchannel 32 is not likely to be disturbed by the partial backflow or theentire backflow, the deterioration of the accuracy of the flow ratedetection by the flow rate detector 22 can be inhibited. Further, evenif the entire backflow occurs, the dynamic pressure due to the entirebackflow is less likely to be received by the measurement outlet 33 c,so that the flow of the intake air in the measurement flow channel 32 isless likely to be disturbed by the entire backflow. This also makes itpossible to inhibit the deterioration of the accuracy of the flow ratedetection by the flow rate detector 22. Therefore, the measurementaccuracy of the intake air amount by the air flow meter 14 can beimproved.

According to the present embodiment, in the flat surface 44, since thedownstream flat portion 137 a extends from the measurement outlet 33 ctoward the downstream side, a configuration can be realized in which themeasurement outlet 33 c is not opened toward the downstream side. Inthat case, the measurement outlet 33 c and the outer peripheraldownstream end 132 b are separated from each other in the depthdirection Z by an amount corresponding to the downstream flat portion137 a. For that reason, even if the turbulence of the air due to thepartial backflow or the entire backflow occurs around the outerperipheral downstream end 132 b in the intake passage 12, the downstreamflat portion 137 a can inhibit the turbulence from reaching themeasurement outlet 33 c.

According to the present embodiment, on the outer peripheral surface ofthe housing 21, the tip-side flat portion 137 b and the base end-sideflat portion 137 c are also disposed between the measurement outlet 33 cand the outer peripheral downstream end 132 b in addition to thedownstream flat portion 137 a. For that reason, even if the turbulenceof the air flow occurs at a position closer to the housing tip side orthe housing base end side than the measurement outlet 33 c in theposition around the outer peripheral downstream end 132 b, the flatportions 137 b and 137 c can inhibit the turbulence from reaching themeasurement outlet 33 c.

According to the present embodiment, in the flat surface 44, theupstream curved portion 138 a extends from the measurement outlet 33 ctoward the upstream side. For that reason, the forward flow air such asthe air AF1 reaching the outer peripheral upstream end 132 a of thehousing 21 flows along the upstream curved portion 138 a, so that theforward flow air is likely to flow along the measurement outlet 33 c,and is less likely to flow into the measurement outlet 33 c. In thatcase, since the dynamic pressure due to the forward flow air is lesslikely to be applied to the measurement outlet 33 c, the turbulence ofthe air flow in the measurement flow channel 32 due to the dynamicpressure and the deterioration of the detection accuracy of the flowrate detector 22 can be inhibited.

In addition, in the depth direction Z, the measurement outlet 33 c isdisposed at the downstream end portion of the curved surface 45 in thecurved surface 45 in which a portion having the largest degree ofbending is disposed at the position closer to the outer peripheralupstream end 132 a. In that case, since the measurement outlet 33 c ishardly opened toward the upstream side, the probability that the air,which has proceeded straight in the depth direction Z among the forwardflow air, directly reaches the measurement outlet 33 c is low. Thismakes it difficult to cause the forward flow air to flow into themeasurement outlet 33 c and to apply the dynamic pressure to themeasurement outlet 33 c.

According to the present embodiment, on the outer peripheral surface ofthe housing 21, the tip-side curved portion 138 b and the base end-sidecurved portion 138 c are also disposed between the measurement outlet 33c and the outer peripheral upstream end 132 a in addition to theupstream curved portion 138 a. For that reason, among the forward flowair flowing along the curved surface 45, the air flowing obliquely tothe depth direction Z also flows along the curved portions 138 b and 138c, so that the traveling direction in the width direction X is changedso as to be less likely to flow into the measurement outlet 33 c. Inthat case, the dynamic pressure due to the forward flow air can be madeless likely to be applied to the measurement outlet 33 c.

According to the present embodiment, the downstream defining surface 135b defining the outlet downstream end 134 b of the measurement outlet 33c is not orthogonal to the depth direction Z, but inclined toward theouter peripheral side of the housing 21. For that reason, since the airAF5 flowing out from the measurement outlet 33 c flows along thedownstream defining surface 135 b, the traveling direction of the air islikely to come closer to the traveling direction of the forward flow airflowing through the intake passage 12. In that instance, since the airAF5 is less likely to be separated from the downstream flat portion 137a, the turbulence of the air flow attributable to the separation is lesslikely to occur around the measurement outlet 33 c. Therefore, thedetection accuracy of the flow rate detector 22 can be inhibited frombeing deteriorated due to the fact that the air flowing through themeasurement flow channel 32 is less likely to flow out from themeasurement outlet 33 c.

According to the present embodiment, the measurement outlet 33 c isdisposed at a position closer to the outer peripheral upstream end 132 ain the depth direction Z. In that case, since the separation distancebetween the outer peripheral downstream end 132 b and the measurementoutlet 33 c in the housing 21 is as large as possible, even ifturbulence of the air flow accompanied by the backflow occurs around theouter peripheral downstream end 132 b, the turbulence can be morereliably inhibited from reaching the measurement outlet 33 c.

According to the present embodiment, since the open area of themeasurement outlet 33 c is smaller than the open area of the inflow port33 a, the forward flow air such as the air AF1 is more likely to flowinto the measurement outlet 33 c than into the inflow port 33 a. Forthat reason, the forward flow air can be inhibited from flowing into themeasurement outlet 33 c.

According to the present embodiment, the measurement outlet 33 c has aflat shape extending in the height direction Y. For that reason, when aplacement region in which the measurement outlet 33 c is necessarily tobe placed is set in the intake passage 12, even if an insertion depth ofthe air flow meter 14 into the airflow insertion hole 12 b variessomewhat from vehicle to vehicle, a part of the measurement outlet 33 ccan be reliably placed in the placement region. In that case, unlike thepresent embodiment, for example, a separation distance between themeasurement outlet 33 c and the outer peripheral downstream end 132 b inthe depth direction Z is larger than that in the configuration in whichthe measurement outlet 33 c is flat and extends in the depth directionZ. Therefore, even if turbulence of the air flow occurs around the outerperipheral downstream end 132 b in the intake passage 12, the flatsurface 44 can inhibit the turbulence from reaching the measurementoutlet 33 c.

<Description of Configuration Group C>

A configuration group C relating to a positional relationship betweenthe housing attachment and the position holder will be described withreference to FIGS. 29 and 30 and the like. In FIG. 30, the connectorterminals 28 a, the SA protrusions 71 a and 71 b, and the width housingprotrusion 72 a are not shown.

As shown in FIG. 8, FIG. 29, and FIG. 30, in the housing 21, the regionstep surface 66 is disposed closer to the housing tip side than the ringholding portion 25. The housing body 24 has an accommodation wallportion 121 defining the accommodation region PB1 and a sealing wallportion 122 defining the sealing region PA, and both of the wallportions 121 and 122 are cylindrical portions extending in the heightdirection Y. The sealing wall portion 122 is provided closer to thehousing base end side than the accommodation wall portion 121, and thesealing wall portion 122 and the accommodation wall portion 121 areconnected to each other by an overhanging portion 66 a. In that case,the overhanging portion 66 a is also included in the housing body 24,and the overhanging portion 66 a corresponds to a housing connector. Theaccommodation wall portion 121 corresponds to a housing wall portion.

The sealing wall portion 122 has an inner peripheral surface disposedcloser to the outer peripheral side than the inner peripheral surface ofthe accommodation wall portion 121, and has an outer peripheral surfacedisposed closer to the outer peripheral side than the outer peripheralsurface of the accommodation wall portion 121. In the overhangingportion 66 a, an intermediate portion between the accommodation wallportion 121 and the sealing wall portion 122 bulges to the outerperipheral side. The overhanging portion 66 a has a lateral extendingportion 66 b extending from the accommodation wall portion 121 towardthe outer peripheral side and a vertical extending portion 66 cextending from the sealing wall portion 122 toward the housing tip side,and the connection portions of those extending portions 66 b and 66 care chamfered by curved surfaces. The lateral extending portion 66 bcorresponds to an orthogonal portion extending in a direction orthogonalto the height direction Y.

In the housing 21, a housing attachment attached to the intake pipe 12 aincludes the ring holding portion 25, the flange portion 27, and thesealing wall portion 122. The ring holding portion 25, the flangeportion 27, and the sealing wall portion 122 have a shape in which thehousing attachment as a whole extends in the width direction X and thedepth direction Z along the peripheral portion of the housing 21. Inthat case, the height direction Y is orthogonal to a direction in whichthe housing attachment extends. The ring holding portion 25 is fixed tothe intake pipe 12 a through an O-ring 26, and the flange portion 27 isfixed to the intake pipe 12 a through the bosses 12 d. In that case, aload for fixing the air flow meter 14 to the intake pipe 12 a is appliedto the sealing wall portion 122 through the ring holding portion 25 andthe flange portion 27. Therefore, since the sealing wall portion 122 isthickened as a whole, a strength of the sealing wall portion 122 isincreased.

In the sealing wall portion 122, an outer peripheral end of a lateralcross section is generally circular, while an inner peripheral end ofthe lateral cross section is generally rectangular. The sealing wallportion 122 enters the airflow insertion hole 12 b of the intake pipe 12a, and the outer peripheral surface of the sealing wall portion 122 suchas the ring holding portion 25 faces the inner peripheral surface of theairflow insertion hole 12 b and the inner peripheral surface of the pipeflange 12 c. In this example, the airflow insertion hole 12 b is formedin a circular shape, and the outer peripheral end of the sealing wallportion 122 is formed in a circular shape in accordance with the shapeof the airflow insertion hole 12 b. In this case, since the separationdistance between the outer peripheral surface of the sealing wallportion 122 and the inner peripheral surface of the airflow insertionhole 12 b is made uniform, the O-ring 26 can easily secure theairtightness between the outer peripheral surface and the innerperipheral surface.

On the other hand, as described above, the sensor SA 50 is inserted intothe internal space 24 a defined by the inner peripheral surface of thehousing body 24, and the inner peripheral surface of the sealing wallportion 122 faces the outer peripheral surface of the sensor SA 50. Inthis example, the sensor SA 50 has a flat cross-sectional shape due tothe plate shape of the sensor SA 50 as a whole, and the inner peripheralend of the sealing wall portion 122 is formed in a flat shape inaccordance with the cross-sectional shape of the sensor SA 50. Thelateral cross section of the sealing wall portion 122 is a cross sectionextending in a direction orthogonal to the height direction Y. Theinternal space 24 a corresponds to an accommodation space in which thesensor SA 50 is accommodated.

As described above, the outer circumference of the sealing wall portion122 is circular and the inner circumference of the sealing wall portion122 is flat, as a result of which the thickness dimension D21 of thesealing wall portion 122 is not uniform in the circumferentialdirection. A pair of SA plate surfaces 125, which are a pair of platesurfaces, and a pair of SA side surfaces 126, which are a pair of sidesurfaces, are included in the outer peripheral surface of the sensor SA50, which is a plate shape as a whole. The SA plate surface 125 as awhole extends in the depth direction Z, and the SA side surface 126 as awhole extends in the width direction X. In the sealing wall portion 122,a portion of the sensor SA 50 facing the SA plate surface 125 is thickeras a whole than a portion facing the SA side surface 126. In this case,in the sealing wall portion 122, a portion having the largest thicknessdimension D21 is included in a portion facing the SA plate surface 125.The SA plate surface 125 is also a plate surface extending in the heightdirection Y in the sensor SA 50.

The ring holding portion 25 is formed by a holding groove 25 a providedin the sealing wall portion 122. In this example, if the holding groove25 a is formed by a pair of groove defining portions, the tip end facesof those groove defining portions are included in the outer peripheralsurface of the sealing wall portion 122. For that reason, the thicknessdimension D21 of the sealing wall portion 122 is a separation distancebetween the inner peripheral surface of the sealing wall portion 122 andthe tip end face of the groove defining portion. The pair of groovedefining portions may protrude from the outer peripheral surface of thesealing wall portion 122. In this case, since the groove definingportion is not included in the sealing wall portion 122, the thicknessdimension D21 of the sealing wall portion 122 is a separation distancebetween the inner peripheral surface of the sealing wall portion 122 andthe bottom surface of the holding groove 25 a. Further, the O-ring 26 isa sealing member which is in close contact with the sealing wall portion122 side and the intake pipe 12 a side to restrict the intake air fromleaking out of the airflow insertion hole 12 b, and the O-ring 26 canalso be referred to as a packing member. In this case, the ring holdingportion 25 corresponds to a sealing holder.

In the accommodation wall portion 121, both the outer peripheral end andthe inner peripheral end of the lateral cross section are flattened as awhole. This is because, unlike the sealing wall portion 122, the outerperipheral surface of the accommodation wall portion 121 does not facethe inner peripheral surface of the airflow insertion hole 12 b, and theshape of the outer peripheral end of the sealing wall portion 122 doesnot need to be matched with the shape of the airflow insertion hole 12b. Since both the outer peripheral end and the inner peripheral end ofthe accommodation wall portion 121 are flattened in this manner, thethickness dimension D22 of the accommodation wall portion 121 issubstantially uniform in the circumferential direction. In other words,in the accommodation wall portion 121, in order to make the thicknessdimension D22 uniform in the circumferential direction, the shape of theouter peripheral surface is set in accordance with the shape of theinner peripheral surface.

The accommodation wall portion 121 is thinner as a whole than thesealing wall portion 122. As compared between the wall thicknesses ofthe accommodation wall portion 121 and the sealing wall portion 122,there is a portion in which the sealing wall portion 122 is thicker thanthe accommodation wall portion 121, but there is no portion in which thesealing wall portion 122 is thinner than the accommodation wall portion121. In other words, the thickness dimension D21 of the thickest portionof the sealing wall portion 122 is larger than the thickness dimensionD22 of any portion of the accommodation wall portion 121, and thethickness dimension D21 of the thinnest portion of the sealing wallportion 122 is not smaller than the thickness dimension D22 of anyportion of the accommodation wall portion 121.

The overhanging portion 66 a is not only thinner than the sealing wallportion 122, but also thinner as a whole than the accommodation wallportion 121. As compared between the wall thicknesses of the overhangingportion 66 a and the accommodation wall portion 121, there is a portionin which the accommodation wall portion 121 is thicker than theoverhanging portion 66 a, but there is no portion in which theaccommodation wall portion 121 is thinner than the overhanging portion66 a.

In the housing 21, the region step surface 66 is formed by an end faceof the housing base end side of the accommodation wall portion 121. Asdescribed above, the circuit step surface 55 of the sensor SA 50 iscaught by the region step surface 66, and the region step surface 66 isheld in position in the height direction Y so as not to move the sensorSA 50 toward the housing because the region step surface 66 is incontact with the sensor SA 50. The region step surface 66 is a surfaceorthogonal to the height direction Y and corresponds to a third holdingportion. The circuit step surface 55 corresponds to a unit contactportion that is in contact with the region step surface 66. The regionstep surface 66 may be referred to as a positioning surface fordetermining and obtaining the position of the sensor SA 220.

The region step surface 66 is also formed by an end face of theaccommodation wall portion 121 on the housing base end side and asurface of the lateral extending portion 66 b on the housing base endside. For that reason, if the circuit step surface 55 of the sensor SA50 is caught by the region step surface 66, the circuit step surface 55may touch not only the accommodation wall portion 121 but also thelateral extending portion 66 b.

As described above, the housing body 24 has housing protrusions 72 a and72 b for holding the sensor SA 50 in place (refer to FIGS. 14 and 15),and the housing protrusions 72 a and 72 b are included in theaccommodation wall portion 121. As shown in FIG. 31, the SA side surface126 of the sensor SA 50 includes inclined surfaces 126 a and 126 b thatare inclined without being perpendicular to the depth direction Z. Theinclined surfaces 126 a and 126 b are included in the outer peripheralsurface of the junction portion 52 of the sensor SA 50. The frontinclined surface 126 a faces the front side of the sensor SA 50, and theback inclined surface 126 b faces the back side of the sensor SA 50.

When the width direction X corresponds to a first direction, the widthhousing protrusion 72 a comes in contact with the SA plate surface 125,thereby holding the sensor SA 50 in position in the width direction Xand corresponds to a first holding portion. This is because the SA platesurface 125 is orthogonal to the width direction X. On the other hand,when the depth direction Z corresponds to a second direction, the depthhousing protrusion 72 b comes in contact with the front inclined surface126 a, thereby holding the sensor SA 50 in position in both the widthdirection X and the depth direction Z, and corresponds to both the firstholding portion and the second holding portion. This is because thefront inclined surface 126 a is inclined with respect to both the widthdirection X and the depth direction Z.

In this manner, the sensor SA 50 comes in contact with the region stepsurface 66 of the accommodation wall portion 121 and the housingprotrusions 72 a and 72 b, and is thus held in position in all of thewidth direction X, the height direction Y, and the depth direction Z. Inthat case, the accommodation wall portion 121 has a first holdingportion, a second holding portion, and a third holding portion, andcorresponds to a position holder. At least a part of the contact portionbetween the accommodation wall portion 121 and the sensor SA 50 isbonded by bonding using an adhesive or welding using a molten resin. Forexample, the region step surface 66 of the accommodation wall portion121 and the circuit step surface 55 of the sensor SA 50 are joined toeach other, and the joining portion extends annularly along theperipheral portion of the sensor SA 50. In that case, since a spacebetween the region step surface 66 and the circuit step surface 55 issealed by an adhesive or molten resin, a thermosetting resin isprevented from leaking from the sealing region PA through the spacebetween the region step surface 66 and the circuit step surface 55 whenthe potting portion 65 is formed.

As described above, when the housing 21 is molded with resin using amolten resin obtained by melting a thermoplastic resin, unintentionaldeformation may occur in the housing 21 as the molten resin is cured.Examples of unintentional deformation include sinks and sores, and sinksare depressions, cavities, and the like generated by curing of themolten resin, and sores are deformation after injection and the likecaused by a residual stress or a residual strain caused by a temperaturedifference or the like when the molten resin is cured.

The unintentional deformation due to the resin molding is more likely tooccur in the thicker portion of the housing 21. For example, because thesealing wall portion 122 as a whole is thicker than the accommodationwall portion 121, deformation due to resin molding is more likely tooccur in the sealing wall portion 122 than in the accommodation wallportion 121. For that reason, unlike the present embodiment, forexample, in the configuration in which the region step surface 66 andthe housing protrusions 72 a and 72 b are provided on the sealing wallportion 122, the possibility of unintentional deformation of the regionstep surface 66 and the housing protrusions 72 a and 72 b during resinmolding is increased. In this instance, the positions of the sensor SA50 and the flow rate detector 22 are deviated from designed positionsdue to unintentional deformation of the region step surface 66 and thehousing protrusions 72 a and 72 b, and the detection accuracy of theflow rate detector 22 is lowered.

On the other hand, since the accommodation wall portion 121 is thinneras a whole than the sealing wall portion 122, deformation due to resinmolding is less likely to occur than the sealing wall portion 122.Therefore, in the present embodiment, as described above, the regionstep surface 66 and the housing protrusions 72 a and 72 b are includedin the accommodation wall portion 121 instead of the sealing wallportion 122. In other words, the region step surface 66 and the housingprotrusions 72 a and 72 b are provided closer to the housing tip sidethan the ring holding portion 25 and the flange portion 27. In thatinstance, the positional deviation of the sensor SA 50 and the flow ratedetector 22 are less likely to occur due to unintentional deformationdue to resin molding, and the detection accuracy of the flow ratedetector 22 is less likely to be lowered.

Even in the configuration in which the region step surface 66 and thehousing protrusions 72 a and 72 b are included in the accommodation wallportion 121, it is conceivable that the deformation caused by the resinmolding may occur in the accommodation wall portion 121 to cause thepositional deviations of the sensor SA 50 and the flow rate detector 22to occur. For example, when the position of the sensor SA 50 is deviatedso as to rotate in the width direction X and the depth direction Z withthe contact portions with the region step surface 66 and the housingprotrusions 72 a and 72 b as fulcrums, the flow rate detector 22 maydeviate in the width direction X and the depth direction Z.

Therefore, in the sensor SA 50 according to the present embodiment, inthe height direction Y, a separation distance L3 between the flow ratedetector 22 and the circuit step surface 55 is smaller than a separationdistance L4 between the end portion on the housing base end side and thecircuit step surface 55. In other words, in the height direction Y, thecircuit step surface 55 is provided at a position closer to the flowrate detector 22. In this example, when the sensor SA 50 rotates withthe contact portion with the accommodation wall portion 121 as afulcrum, as a rotation radius of the flow rate detector 22 is smaller, apositional deviation amount of the flow rate detector 22 in the widthdirection X and the depth direction Z is smaller. As described above, asthe separation distance L3 between the circuit step surface 55 and theflow rate detector 22 in the height direction Y is smaller, thepositional deviation amount of the flow rate detector 22 is smaller, andthe detection accuracy of the flow rate detector 22 is less likely to belowered.

In the present embodiment, the separation distance between the centerportion of the detection element 22 b of the flow rate detector 22 andthe circuit step surface 55 in the height direction Y is defined as theseparation distance L3. However, the separation distance L3 may be avalue indicating the degree of separation between the flow rate detector22 and the circuit step surface 55, and may be, for example, aseparation distance between the end portion of the flow rate detector 22on the housing base end side and the circuit step surface 55 in theheight direction Y.

In the internal space 24 a of the housing body 24, a volume V1 of theaccommodation region PB1 is smaller than a volume V2 of the sealingregion PA because the separation distance L3 is smaller than theseparation distance L4. In other words, when the volume V1 of theaccommodation region PB1 is smaller than the volume V2 of the sealingregion PA, there is a high possibility that the circuit step surface 55is provided at a position closer to the flow rate detector 22 in theheight direction Y in the sensor SA 50. Further, in the internal space24 a, when a region between the region step surface 66 and the endportion of the sensor SA 50 on the housing tip side in the heightdirection Y is referred to as a detection region PB3 in which the flowrate detector 22 is accommodated, a volume V3 of the detection regionPB3 is smaller than the volume V2 of the sealing region PA. On the otherhand, the volume V3 of the detection region PB3 is larger than thevolume V1 of the accommodation region PB1. The detection region PB3 is aregion including the entire accommodation region PB1 and a portion ofthe measurement region PB2 on the housing base end side.

If any deformation caused by the molding of the resin slightly occurs inthe accommodation wall portion 121, when the operator inserts the sensorSA 50 into the accommodation wall portion 121 at the time ofmanufacturing the air flow meter 14, the sensor SA 50 may be distortedin accordance with the deformation of the accommodation wall portion121. For example, when the upstream side portion and the downstream sideportion of the region step surface 66 are displaced in the heightdirection Y, the sensor SA 50 may be distorted such that the upstreamside portion and the downstream side portion of the circuit step surface55 are displaced in the height direction Y. If the position of the flowrate detector 22 deviates from a designed position due to the distortionof the sensor SA 50, the detection accuracy of the flow rate detector 22is likely be lowered.

Therefore, in the sensor SA 50 of the present embodiment, the flow ratedetector 22 is disposed at a position as far as possible from thecircuit step surface 55. Specifically, in the height direction Y, theseparation distance L3 between the flow rate detector 22 and the regionstep surface 66 is larger than the thickness dimension D22 of thelateral extending portion 66 b. In other words, the flow rate detector22 is disposed closer to the housing tip side than the overhangingportion 66 a. In that instance, for example, even if a portion of thesensor SA 50 in the vicinity of the circuit step surface 55 is distorteddue to the occurrence of the deformation caused by resin molding in theregion step surface 66 of the housing body 24, the distortion is lesslikely to reach the flow rate detector 22. For that reason, even if thedeformation due to resin molding occurs in the region step surface 66 ofthe accommodation wall portion 121, the flow rate detector 22 is lesslikely to be displaced.

In the sensor SA 50, the SA protrusions 71 a and 71 b are providedbetween the circuit step surface 55 and the flow rate detector 22 in theheight direction Y, and from the above viewpoint, it is conceivable thatthe flow rate detector 22 is disposed as far as possible from thecircuit step surface 55. In particular, the SA protrusions 71 a and 71 bextend in the height direction Y, and a spacing dimension between thecircuit step surface 55 and the flow rate detector 22 in the heightdirection Y is larger than the longitudinal dimension of the SAprotrusions 71 a and 71 b. Therefore, even if deformation due to resinmolding occurs in the region step surface 66, the distortion is lesslikely to reach the flow rate detector 22 in the sensor SA 50.

Since the flow rate detector 22 is located as far as possible from thecircuit step surface 55, the flow rate detector 22 is also separatedfrom the ring holding portion 25. In that case, in the air flow meter14, even if a heat is applied from the internal combustion engine 11 orthe like to the housing body 24, the flange portion 27, and the pottingportion 65 outside the intake pipe 12 a, the heat is less likely to betransmitted to the flow rate detector 22. For that reason, the detectionaccuracy of the flow rate detector 22 is less likely to be lowered by aheat from the outside of the intake pipe 12 a.

In the sensor SA 50 of the present embodiment, as shown in FIG. 29, theflow rate detector 22 is disposed at a position as far as possible fromthe accommodation wall portion 121 in the depth direction Z.Specifically, a separation distance L5 between the flow rate detector 22and the accommodation wall portion 121 in the depth direction Z islarger than the thickness dimension D23 of the accommodation wallportion 121. The separation distance L5 is larger than a thicknessdimension D23 of the thickest portion of the accommodation wall portion121. The flow rate detector 22 is disposed at the center position of theaccommodation region PB1 in the depth direction Z, and for that reason,the separation distance L5 is ½ of the depth dimension D6 of theaccommodation region PB1 in the depth direction Z (refer to FIG. 8). Inaddition, in a portion of the accommodation wall portion 121 where thehousing protrusions 72 a and 72 b are present, the protrusion dimensionsof the housing protrusions 72 a and 72 b are included in the thicknessdimension D23.

In that instance, for example, even if a portion of the sensor SA 50 inthe vicinity of the outer peripheral surface of the junction portion 52is distorted due to the deformation caused by the resin moldingoccurring in the depth housing protrusion 72 b of the accommodation wallportion 121, the distortion is less likely to reach the flow ratedetector 22. For that reason, even if the deformation due to resinmolding occurs in the depth housing protrusion 72 b of the accommodationwall portion 121, the flow rate detector 22 is hardly displaced.

In the present embodiment, the separation distance between the centralportion of the flow rate detector 22 and the inner peripheral surface ofthe accommodation wall portion 121 in the depth direction Z is definedas a separation distance L5. However, the separation distance L5 may bea value indicating the degree of separation between the flow ratedetector 22 and the accommodation wall portion 121 in the depthdirection Z, and may be, for example, a spacing dimension between theflow rate detector 22 and the accommodation wall portion 121 in thedepth direction Z.

Next, a manufacturing method of the air flow meter 14 will be describedwith reference to FIGS. 14, 29, and 30, focusing on a process ofmounting the sensor SA 50 to the housing 21.

After the housing 21 has been molded with resin by using the mold device90, the sensor SA 50 is inserted into the internal space 24 a throughthe housing opening 61. When the junction portion 52 of the sensor SA 50is fitted into the accommodation wall portion 121, the front SAprotrusion 71 a deforms the width housing protrusion 72 a, and thejunction portion 52 deforms the depth housing protrusion 72 b. When thesensor SA 50 is inserted into the internal space 24 a and the circuitstep surface 55 of the sensor SA 50 is pressed against the region stepsurface 66 of the housing 21, the insertion of the sensor SA 50 isterminated. The housing opening 61 corresponds to an accommodationopening for accommodating the sensor SA 50 in the internal space 24 a.

In that instance, since the tip end face of the width housing protrusion72 a comes in contact with the tip end face of the front SA protrusion71 a, the sensor SA 50 is restricted from moving toward the widthhousing protrusion 72 a in the width direction X. On the other hand, thesensor SA 50 is prevented from moving away from the width housingprotrusion 72 a because the back SA protrusion 71 b of the sensor SA 50comes in contact with the inner peripheral surface of the accommodationwall portion 121. In that case, the tip end face of the width housingprotrusion 72 a and a portion of the inner peripheral surface of theaccommodation wall portion 121 which comes in contact with the back SAprotrusion 71 b can be referred to as a positioning surface.

Further, in that instance, since the tip end face of the depth housingprotrusion 72 b comes in contact with the upstream side end face of thejunction portion 52, the sensor SA 50 is restricted from moving towardthe depth housing protrusion 72 b in both the width direction X and thedepth direction Z. On the other hand, the sensor SA 50 is restrictedfrom moving away from the depth housing protrusion 72 b because thedownstream side surface of the sensor SA 50 comes in contact with theinner peripheral surface of the accommodation wall portion 121. In thatinstance, a portion of the tip end face of the depth housing protrusion72 b or the inner peripheral surface of the accommodation wall portion121, with which the downstream side end face of the sensor SA 50 comesin contact may be referred to as a positioning surface.

Further, since the circuit step surface 55 of the sensor SA 50 comes incontact with the region step surface 66 of the housing 21, the sensor SA50 is restrained from moving toward the housing tip side in the heightdirection Y. On the other hand, the movement of the sensor SA 50 towardthe housing base end side is restricted by fitting the junction portion52 of the sensor SA 50 into the accommodation wall portion 121.

After the sensor SA 50 has been inserted into the internal space 24 a, athermosetting resin such as a potting resin is injected into theinternal space 24 a, and the thermosetting resin is cured to form thepotting portion 65. In this instance, the movement of the sensor SA 50toward the housing base end side is also restricted by the pottingportion 65.

In the configuration group C, according to the present embodiment, inthe housing 21, the accommodation wall portion 121 is separated from thering holding portion 25 toward the housing tip side. For that reason,the ring holding portion 25 can be thickened to improve the strength,while the accommodation wall portion 121 can be thinned so as not to bedeformed by resin molding. As described above, since the accommodationwall portion 121 is thinned, the shapes of the accommodation wallportions 121 are less likely to vary from product to product, andtherefore, the position of the sensor SA 50 positioned by theaccommodation wall portion 121 is less likely to vary. Therefore, thedetection accuracy of the flow rate detector 22 can be inhibited fromvarying from product to product.

According to the present embodiment, the housing opening 61 is providedcloser to the housing base end side than the region step surface 66. Inthis example, there is a concern that the housing body 24 isunintentionally deformed due to the relatively low strength of theportion of the housing 21 where the housing opening 61 is provided. Onthe other hand, in the housing 21, the strength of the housing 21 isenhanced by the sealing wall portion 122, the ring holding portion 25,and the flange portion 27 on the housing base end side of the regionstep surface 66. Therefore, the housing opening 61 is provided in aportion of the housing 21 where the strength on the housing base endside is more easily secured than the region step surface 66, therebybeing capable of inhibiting unintentional deformation of the housingbody 24 due to the presence of the housing opening 61. As a result, thepositional deviation of the sensor SA 50 caused by the deformation ofthe housing body 24 can be inhibited.

According to the present embodiment, both the width housing protrusion72 a for regulating the movement of the sensor SA 50 in the widthdirection X and the depth housing protrusion 72 b for regulating themovement of the sensor SA 50 in the depth direction Z are included inthe accommodation wall portion 121. In this instance, since the housingprotrusions 72 a and 72 b of the accommodation wall portion 121 are lesslikely to be deformed by the resin molding, the position of the sensorSA 50 in the width direction X and the depth direction Z can beinhibited from varying from product to product.

According to the present embodiment, a large part of the innerperipheral surface of the accommodation wall portion 121 does not comein contact with the outer peripheral surface of the sensor SA 50, butlimited parts such as the tip portions of the housing protrusions 72 aand 72 b come in contact with the outer peripheral surface of the sensorSA 50. In that case, even if the deformation attributable to the resinmolding occurs in the accommodation wall portion 121, the housingprotrusions 72 a and 72 b are not necessarily displaced in position orthe housing protrusions 72 a and 72 b themselves are deformed by thedeformation of the accommodation wall portion 121. For that reason, evenif the shape variation of each product occurs in the accommodation wallportion 121, the position of the sensor SA 50 does not easily vary dueto the deformation variation. This makes it possible to more reliablyinhibit variations in the position of the sensor SA 50 from product toproduct.

According to the present embodiment, the accommodation wall portion 121includes the region step surface 66 that restricts the sensor SA 50 frommoving toward the housing tip side in the height direction Y. In thisinstance, in the accommodation wall portion 121, since the deformationof the region step surface 66 due to the resin molding is less likely tobe generated, the position of the sensor SA 50 in the height direction Ycan be inhibited from varying from product to product.

According to the present embodiment, in the sensor SA 50, the circuitstep surface 55 is provided between the lead terminals 54 and the flowrate detector 22 at a position closer to the flow rate detector 22. Inthis instance, even if the sensor SA 50 is deviated in position so as torotate about the contact portion with the region step surface 66 as afulcrum, the amount of positional deviation of the flow rate detector 22can be reduced as compared with a configuration in which the circuitstep surface 55 is provided at a position closer to the lead terminals54, for example. For that reason, the deterioration of the detectionaccuracy of the flow rate detector 22 can be inhibited.

According to the present embodiment, since the ring holding portion 25and the accommodation wall portion 121 are connected to each other bythe overhanging portion 66 a, a configuration can be realized in whichthe accommodation wall portion 121 is separated from the ring holdingportion 25 toward the housing tip side. In that case, even if thedeformation caused by the resin molding occurs in the ring holdingportion 25, the deformation is absorbed by the overhanging portion 66 a,so that the position and the shape of the accommodation wall portion 121are less likely to change with the deformation of the ring holdingportion 25. For that reason, the positioning accuracy of the sensor SA50 by the region step surface 66 and the housing protrusions 72 a and 72b can be inhibited from being deteriorated.

According to the present embodiment, since the separation distance L3between the flow rate detector 22 and the region step surface 66 islarger than the thickness dimension D22 of the lateral extending portion66 b, a configuration can be realized in which the flow rate detector 22is moved away as far as possible from the region step surface 66 in theheight direction Y. According to the above configuration, even if thedeformation caused by the resin molding is generated in the region stepsurface 66, the distortion generated in the sensor SA 50 by fitting thesensor SA 50 inside the accommodation wall portion 121 is less likely toreach the flow rate detector 22. For that reason, even if the sensor SA50 is distorted when the sensor SA 50 is assembled to the housing 21,the positional deviation of the flow rate detector 22 can be inhibited.

According to the present embodiment, since the separation distance L5between the flow rate detector 22 and the accommodation wall portion 121is larger than the thickness dimension D23 of the accommodation wallportion 121, a configuration can be realized in which the flow ratedetector 22 is moved away as far as possible from the accommodation wallportion 121 in the depth direction Z. According to the aboveconfiguration, even if the housing protrusions 72 a and 72 b aredeformed due to the resin molding, the distortion generated in thesensor SA 50 is less likely to reach the flow rate detector 22 byfitting the housing protrusions 72 a and 72 b inside the accommodationwall portion 121. This makes it possible to inhibit the positionaldeviation of the flow rate detector 22 from occurring due to thedistortion of the sensor SA 50.

According to the present embodiment, the sensor SA 50 is inserted intothe internal space 24 a through the housing opening 61. As describedabove, even when the sensor SA 50 is added to the resin-molded housing21 later, the positioning accuracy of the sensor SA 50 by theaccommodation wall portion 121 can be enhanced because the deformationdue to the resin molding is less likely to be generated in theaccommodation wall portion 121.

<Description of Configuration Group D>

A configuration group D relating to the configuration of the passageflow channel will be described with reference to FIGS. 32, 33, and thelike.

As shown in FIG. 32, the passage flow channel 31 does not extenddownstream of the flow channel boundary portion 34 in the depthdirection Z. In other words, in the passage flow channel 31, a portionbetween the flow channel boundary portion 34 and the inflow port 33 a inthe depth direction Z is the inflow passage 31 a, and there is noportion between the flow channel boundary portion 34 and the outflowport 33 b in the depth direction Z. In that case, a part of the flowchannel boundary portion 34 and a part of the outflow port 33 b overlapwith each other, and the flow channel boundary portion 34 extends fromthe outflow port 33 b toward the inflow port 33 a in the depth directionZ. The flow channel boundary portion 34 corresponds to a branchboundary.

The inner peripheral surface of the passage flow channel 31 has apassage ceiling surface 151, a passage floor surface 152, and a passagewall surface 153. The passage ceiling surface 151 and the passage floorsurface 152 are opposed to each other across the passage flow channel 31in the height direction Y, and the passage ceiling surface 151 isdisposed closer to the housing base end side than the passage flowchannel 31. The passage ceiling surface 151 faces the housing tip side,and the passage floor surface 152 faces the housing base end side. Thepair of passage wall surfaces 153 are provided across the passageceiling surface 151 and the passage floor surface 152 in the widthdirection X, and those passage wall surfaces 153 are opposed to eachother in a state of being directed in the width direction X.

The inner peripheral surface of the passage flow channel 31 has throttlesurfaces 152 a and 153 a that throttle the passage flow channel 31 fromthe inflow port 33 a toward the outflow port 33 b. In that case, theflow channel area of the passage flow channel 31 gradually decreasestoward the outflow port 33 b. The throttle surfaces 152 a and 153 a areincluded in the inner peripheral surface of the outflow passage 31 b,and extend from the outflow port 33 b toward the inflow passage 31 a.The throttle surfaces 152 a and 153 a are inclined with respect to thedepth direction by being directed toward the inflow port 33 a side. Thethrottle surfaces 152 a and 153 a extend over the upstream end portionand the downstream end portion of the outflow passage 31 b, and are notincluded in the inner peripheral surface of the inflow passage 31 a. Theflow path cross section of the passage flow channel 31 is smaller in theportion closer to the outflow port 33 b in the outflow passage 31 b.

The floor throttle surface 152 a is included in the passage floorsurface 152, and the wall throttle surface 153 a is included in thepassage wall surface 153. The floor throttle surface 152 a is an innerperipheral surface of a portion of the housing bottom portion 62 whichis inclined with respect to the depth direction Z. The wall throttlesurface 153 a is an inner peripheral surface of the passage throttleportion 47, and a pair of the wall throttle surfaces 153 a are providedacross the floor throttle surface 152 a in the width direction X. Thefloor throttle surface 152 a and the wall throttle surface 153 acorrespond to a passage throttle surface.

The flow channel boundary portion 34 is inclined with respect to thedepth direction Z by being directed toward the outflow port 33 b. Inother words, the flow channel boundary portion 34 is inclined withrespect to the passage ceiling surface 151. The flow channel boundaryportion 34 faces the floor throttle surface 152 a across the outflowport 33 b, and extends in parallel with the floor throttle surface 152a.

The outer peripheral surface of the housing 21 includes an eaves surface154 extending toward the outer peripheral side from an overlappingportion of the inflow port 33 a and the flow channel boundary portion34. The eaves surface 154 is disposed on the opposite side of thepassage ceiling surface 151 across the flow channel boundary portion 34in the depth direction Z, and extends in the depth direction Z similarlyto the passage ceiling surface 151. For that reason, the floor throttlesurface 152 a is also inclined with respect to the eaves surface 154.The eaves surface 154 does not define the passage flow channel 31because the passage wall surface 153 is not connected to the eavessurface 154.

Next, the passage mold portion 104 of the mold device 90 will bedescribed.

As shown in FIGS. 32 and 33, the outer peripheral surface of the passagemold portion 104 has a floor throttle molding surface 156 for moldingthe floor throttle surface 152 a and a wall throttle molding surface 157for molding the wall throttle surface 153 a. The passage mold portion104 has an outer passage surface 158 that abuts against the outerperipheral mold portions 102 and 103 in an assembled state of the molddevice 90, and the outer passage surface 158 is a tip portion or a tipend face of the passage mold portion 104. The floor throttle moldingsurface 156 and the wall throttle molding surface 157 extend in thedepth direction Z from the outer passage surface 158 of the passage moldportion 104. With the provision of the molding surfaces 156 and 157, thepassage mold portion 104 is thinner in a portion closer to the outerpassage surface 158. A pair of the wall throttle molding surfaces 157are provided across the floor throttle molding surface 156 in the widthdirection X. The floor throttle molding surface 156 and the wallthrottle molding surface 157 correspond to a mold throttle portion.

The outer peripheral surface of the passage mold portion 104 has aninner passage surface 159 that abuts against the introduction moldingportion 97 b in a state in which the mold device 90 is assembled. Theinner passage surface 159 is disposed on the opposite side of thepassage mold portion 104 across the wall throttle molding surface 157and the outer passage surface 158, and is perpendicular to the outerpassage surface 158. The floor throttle molding surface 156 is inclinedwith respect to the inner passage surface 159. As described above, theintroduction molding portion 97 b is included in the measurement moldingportion 97, and the measurement molding portion 97 is included in theinner peripheral mold portion 91. The inner peripheral mold portion 91corresponds to a measurement mold portion and a branch mold portion formolding the inner peripheral surface of the measurement flow channel 32.

In the assembled state of the mold device 90, the measurement moldingportion 97 abuts against both the passage mold portion 104 and the outerperipheral mold portions 102 and 103. The outer peripheral surface ofthe measurement molding portion 97 has an outer measurement surface 161that abuts against the outer peripheral mold portions 102 and 103 in themold device 90, and an inner measurement surface 162 that abuts againstthe inner passage surface 159 of the passage mold portion 104. Beforethe mold device 90 is removed from the resin-molded housing 21, theouter measurement surface 161 and the inner measurement surface 162 aredisposed inside the passage flow channel 31 because the tip portion ofthe measurement molding portion 97 enters the passage flow channel 31.In that case, the outer passage surface 158 of the passage mold portion104 and the outer measurement surface 161 of the measurement moldingportion 97 form the same plane, and the plane is included in the outflowport 33 b. In the measurement molding portion 97, a portion entering thepassage flow channel 31 is referred to as an entry portion 163, and theentry portion 163 is indicated by dot hatching in FIG. 32.

When a portion of the measurement molding portion 97 abutting againstthe first outer peripheral mold portion 102 will be described withreference to an illustration of FIG. 33, the mold device 90, is formedwith a mold boundary 165, which is a boundary between the measurementmolding portion 97, the passage mold portion 104, and the first outerperipheral mold portion 102. The mold boundary 165 extends in the widthdirection X, and the mold boundary 165 includes a boundary between theouter measurement surface 161 and the inner measurement surface 162 ofthe measurement molding portion 97. The mold boundary 165 is disposed atthe outflow port 33 b of the passage flow channel 31 in the housing 21.In a portion of the measurement molding portion 97 abutting against thesecond outer peripheral mold portion 103, a boundary of three moldportions, that is, the measurement molding portion 97, the passage moldportion 104, and the second outer peripheral mold portion 103, may bereferred to as a mold boundary 165.

As described above, when the mold device 90 is detached from theresin-molded housing 21, after the passage mold portion 104 is extractedfrom the inflow port 33 a of the housing 21, the outer peripheral moldportions 102 and 103 are detached from the outer peripheral surface ofthe housing 21. Either the operation of detaching the inner peripheralmold portion 91 from the housing 21 or the operation of detaching thepassage mold portion 104 from the housing 21 may be performed first.

In the configuration group D, according to the present embodiment, theinner peripheral surface of the passage flow channel 31 is integrallymolded by using the mold device 90 at the time of molding the housing 21with resin. For that reason, there is no need to provide the passageflow channel 31 by separately molding multiple members with resin andthen combining those members together. In that case, it is difficult togenerate a step on the inner peripheral surface of the passage flowchannel 31 at the boundary between the members, or to cause the shapeand size of the passage flow channel 31 to vary from product to product.With a reduction in the manufacturing variation in this manner, thedetection accuracy of the flow rate detector 22 can be enhanced.

According to the present embodiment, when the mold device 90 is detachedfrom the resin-molded housing 21, after the passage mold portion 104 hasbeen extracted from the inflow port 33 a of the housing 21, the outerperipheral mold portions 102 and 103 are detached from the outerperipheral surface of the housing 21. In this case, when the passagemold portion 104 is extracted from the inflow port 33 a in the depthdirection Z, the outer peripheral portion of the housing 21 is protectedby the outer peripheral mold portions 102 and 103. For that reason, evenif the passage mold portion 104 is extracted from the inflow port 33 awhile being twisted so that the tip portion of the passage mold portion104 is swung in the width direction X and the height direction Y, thehousing 21 is less likely to be deformed from the inner peripheral sideby the passage mold portion 104. This makes it possible to inhibit thehousing 21 from being deformed or damaged unintentionally when thepassage mold portion 104 is detached from the housing 21.

According to the present embodiment, before the mold device 90 isremoved from the resin-molded housing 21, the entry portion 163 of themeasurement molding portion 97 enters the passage flow channel 31. Inother words, the mold boundary 165 is formed inside the passage flowchannel 31. In this manner, a part of the inner peripheral surface ofthe passage flow channel 31 is molded by the measurement molding portion97, in the mold device 90 in which the passage mold portion 104 is notextracted from the outflow port 33 b, the degree of freedom of designand manufacturing relating to the shape of the passage flow channel 31can be enhanced. For that reason, the housing 21 in which the flowchannel boundary portion 34 faces the outflow port 33 b side can berealized as in the present embodiment.

According to the present embodiment, the passage mold portion 104gradually tapers toward the tip portion forming the outer passagesurface 158. In other words, the passage mold portion 104 has a shapethat does not become thicker. For that reason, when the housing 21 ismolded with resin in a state in which the passage mold portion 104 andthe outer peripheral mold portions 102 and 103 are assembled to eachother, the passage mold portion 104 can be pulled out from the inflowport 33 a of the housing 21 toward the side opposite to the outerpassage surface 158. In this case, the inner peripheral surface of thepassage flow channel 31 can be integrally molded by using the passagemold portion 104.

According to the present embodiment, since the floor throttle moldingsurface 156 and the wall throttle molding surface 157 are included inthe outer peripheral surface of the passage mold portion 104, a shapecan be realized in which the passage mold portion 104 gradually narrowstoward the outer passage surface 158. In this case, in the innerperipheral surface of the passage flow channel 31, an area of a portionof the passage mold portion 104 extending in parallel to the depthdirection Z, which is a drawing direction of the passage mold portion104, is reduced by an amount corresponding to the floor throttle moldingsurface 156 and the wall throttle molding surface 157. For that reason,the passage mold portion 104 can be easily pulled out from the inside ofthe passage flow channel 31.

According to the present embodiment, in the depth direction Z, thepassage flow channel 31 is not narrowed from the outflow port 33 btoward the inflow port 33 a. In that case, since the passage moldportion 104 can be extracted from the inflow port 33 a when the housing21 is molded with resin using the mold device 90, there is no need todefine the passage flow channel 31 by combining multiple members. Unlikethe present embodiment, for example, in the configuration in which theintermediate portion of the passage flow channel 31 is the thickest, itis difficult to extract the passage mold portion 104 from the inflowport 33 a due to the passage mold portion 104 being caught on the innerperipheral surface of the passage flow channel 31. In the aboveconfiguration, since the passage flow channel 31 is defined by combiningmultiple members together, the manufacturing variation of the passageflow channel 31 as described above is likely to occur.

According to the present embodiment, since the floor throttle surface152 a and the wall throttle surface 153 a are included in the innerperipheral surface of the passage flow channel 31, the degree ofthrottling of the passage flow channel 31 can be increased toward theoutflow port 33 b. In addition, since the floor throttle surface 152 aand the wall throttle surface 153 a extend from the outflow port 33 btoward the inflow port 33 a, the degree of throttling of the outflowport 33 b can be maximized in the passage flow channel 31. As a result,even in the configuration in which the outflow port 33 b extends fromthe flow channel boundary portion 34, a flow velocity of the air in themeasurement flow channel 32 can be appropriately increased by narrowingthe outflow port 33 b.

According to the present embodiment, since the outflow port 33 b extendsfrom the flow channel boundary portion 34, there is no need to extendthe passage mold portion 104 to the outflow port 33 b side of the flowchannel boundary portion 34 when molding the housing 21 with resin. Inthat case, a portion of the passage flow channel 31 which is alignedwith the flow channel boundary portion 34 in the height direction Y canbe molded not only by the passage mold portion 104 but also by themeasurement molding portion 97. For that reason, when the housing 21 isformed using the mold device 90 in which the passage mold portion 104 isnot extracted from the outflow port 33 b, the degree of freedom ofdesign and manufacturing relating to the positional relationship betweenthe flow channel boundary portion 34 and the outflow port 33 b can beincreased.

According to the present embodiment, since the flow channel boundaryportion 34 extends from the outflow port 33 b, in the configuration inwhich the inner peripheral surface of the passage flow channel 31 isintegrally molded, the flow channel boundary portion 34 can be inclinedwith respect to the depth direction Z so as to face the outflow port 33b side. In that case, a foreign matter that has entered the passage flowchannel 31 from the inflow port 33 a cannot reach the flow channelboundary portion 34 only by advancing straight toward the outflow port33 b. This makes it possible to inhibit the foreign matter from enteringthe measurement flow channel 32 from the passage flow channel 31.

<Configuration Group E>

A configuration group E relating to the position of the connectorterminals will be described with reference to FIGS. 34 to 39 and thelike. In FIG. 34, the SA protrusions 71 a and 71 b, the width housingprotrusion 72 a, and the terminal fixing portion 87 are omitted, and inFIG. 35, the potting portion 65 is omitted.

As shown in FIG. 34, the connector portion 28 of the air flow meter 14has a connector recess portion 171 in which a tip end face of theconnector portion 28 is recessed. When an open end of the connectorrecess portion 171 is referred to as a connector opening 171 a, theconnector opening 171 a opens an internal space of the connector recessportion 171 in the depth direction Z. In the present embodiment, theheight direction Y corresponds to a direction in which the detectionunit and the housing opening are aligned. The connector opening 171 amay open the internal space of the connector recess portion 171 in thewidth direction X or the height direction Y.

The connector terminal 28 a extends between the connector recess portion171 and the internal space 24 a. The connector terminal 28 a has a firstterminal portion 172 a disposed inside the connector recess portion 171,a second terminal portion 172 b disposed in the internal space 24 a, anda connection terminal portion 172 c connecting the terminal portions 172a and 172 b. In the connector terminal 28 a, one end portion is includedin the first terminal portion 172 a, and the other end portion isincluded in the second terminal portion 172 b. The first terminalportion 172 a extends toward the connector opening 171 a inside theconnector recess portion 171. The second terminal portion 172 b extendstoward the housing opening 61 in the internal space 24 a, but does notprotrude outward from the housing opening 61.

In the connector terminals 28 a, a portion protruding from the innerperipheral surface of the housing 21 into the connector recess portion171 is the first terminal portion 172 a, and a portion protruding fromthe inner peripheral surface of the housing 21 into the internal space24 a is the second terminal portion 172 b. For that reason, the entireconnection terminal portion 172 c is buried in the housing 21 betweenthe internal space 24 a and the connector recess portion 171. At least apart of the connection terminal portion 172 c may be embedded in thehousing 21. Even in this case, a configuration in which the connectionterminal portion 172 c is fixed to the housing 21 can be realized.

In the sensor SA 50, a portion including the circuit accommodationportion 51, the junction portion 52, and the sensing portion 53 isreferred to as an SA main body 170, and the SA main body 170 includesthe flow rate detector 22. The lead terminal 54 extends from the SA mainbody 170 toward the housing opening 61 in the height direction Y, butdoes not protrude outward from the housing opening 61. The SA main body170 corresponds to a unit main body.

The internal space 24 a has a main body region PC1 in which the SA mainbody 170 is accommodated, and a connector region PC2 in which the secondterminal portion 172 b of the connector terminals 28 a is accommodated.The main body region PC1 and the connector region PC2 are alignedlaterally in the width direction X, which is a direction perpendicularto the height direction Y, and both of the main body region PC1 and theconnector region PC2 extend from the housing opening 61 toward thehousing tip side. The main body region PC1 includes a region thatextends over the region step surface 66 and the housing opening 61 inthe height direction Y, and the connector region PC2 is a region thatextends over the sealing step surface 67 and the housing opening 61 inthe height direction Y. In the width direction X, which is a directionperpendicular to the height direction Y, a boundary between the regionstep surface 66 and the sealing step surface 67 is included in aboundary between the main body region PC1 and the connector region PC2.A pair of the region step surfaces 66 is provided across the internalspace 24 a in the width direction X.

The connector region PC2 is disposed at a position spaced apart from theSA main body 170 toward the housing opening 61 in the height directionY. This is because the sealing step surface 67 is disposed between thehousing opening 61 and the SA main body 170 in the height direction Y.

In the connector region PC2, the second terminal portion 172 b of theconnector terminal 28 a extends from the sealing step surface 67 towardthe housing opening 61. In the connector terminal 28 a, the connectionterminal portion 172 c is not exposed to the connector region PC2. Inthis instance, a part of a portion extending from the connectionterminal portion 172 c toward the housing opening 61, which is disposedin the connector region PC2, forms the second terminal portion 172 b.The second terminal portion 172 b corresponds to a protrusion terminalportion and a longitudinal terminal portion.

In the internal space 24 a, the connector terminal 28 a is not insertedbetween the housing opening 61 and the sensor SA 50 in the heightdirection Y. This is because the second terminal portion 172 b does notprotrude from the connector region PC2 to the main body region PC1. Inother words, the connector terminal 28 a does not protrude into the mainbody region PC1.

In the internal space 24 a, the circuit step surface 55 of the sensor SA50 is caught by the region step surface 66 from the housing opening 61.The bridge terminal 86 of the terminal unit 85 is caught by the sealingstep surface 67 from the housing opening 61 side. As described above,both the region step surface 66 and the sealing step surface 67 areincluded in the inner peripheral surface of the housing 21. The regionstep surface 66 corresponds to a unit holding surface that holds theposition of the sensor SA 50 in the height direction Y, and the sealingstep surface 67 corresponds to a terminal holding surface that holds theposition of the bridge terminal 86 in the height direction Y. The bridgeterminal 86 corresponds to a connection terminal.

The bridge terminal 86 has a first bridge portion 173 a connected to thelead terminal 54, a second bridge portion 173 b connected to theconnector terminals 28 a, and a connection bridge portion 173 cconnected to the bridge portions 173 a and 173 b. The bridge terminal 86extends across the boundary between the main body region PC1 and theconnector region PC2 in the width directions X. The first bridge portion173 a extends along the lead terminal 54 in the main body region PC1,and the second bridge portion 173 b extends along the second terminalportion 172 b of the connector terminals 28 a in the connector regionPC2. The connection bridge portion 173 c is bridged between the mainbody region PC1 and the connector region PC2.

The second bridge portion 173 b enters between the sealing step surface67 and the housing opening 61, and at least one of the second bridgeportion 173 b and the connection bridge portion 173 c comes in contactwith the sealing step surface 67. In this case, the sealing step surface67 supports the connection portion between the second bridge portion 173b and the second terminal portion 172 b. The first bridge portion 173 aincludes a second connection portion 86 b (refer to FIG. 18, and so on),and a portion including the second connection portion 86 b is aconnection portion between the first bridge portion 173 a and the leadterminal 54. The second bridge portion 173 b includes a first connectionportion 86 a (refer to FIG. 18, and so on), and a portion including thefirst connection portion 86 a is a connection portion between the secondbridge portion 173 b and the second terminal portion 172 b.

As shown in FIG. 35, the multiple lead terminals 54 included in thesensor SA 50 include a terminal electrically connected to the intake airtemperature terminal 23 c in addition to a terminal electricallyconnected to the connector terminal 28 a. Like the connector terminal 28a, the intake air temperature terminal 23 c is also connected to thelead terminal 54 through the bridge terminal 86. Like the secondterminal portion 172 b of the connector terminals 28 a, the intake airtemperature terminals 23 c has an intake air temperature terminalportion 175 protruding from the sealing step surface 67 to the connectorregion PC2 and extending toward the housing opening 61. In thisinstance, the intake air temperature terminal portion 175 is alsodisposed in the connector region PC2 so as not to protrude into the mainbody region PC1, similarly to the second terminal portion 172 b.

Next, the mold device 90 will be described with reference to FIGS. 22and 36. FIG. 36 illustrates the mold device 90 when the outer peripheralsurface of the second outer peripheral mold portion 103 is viewed fromthe side opposite to the first outer peripheral mold portion 102.

As shown in FIGS. 22 and 36, the mold device 90 has a connector moldportion 177 which is assembled to the inner peripheral mold portion 91and the second outer peripheral mold portion 103. The connector moldportion 177 is assembled to the outer peripheral surface of the secondouter peripheral mold portion 103 in a state of being inserted into theinner peripheral mold portion 91, thereby molding the inner peripheralsurface of the connector portion 28. The connector mold portion 177according to the present embodiment is formed as a separate member fromthe inner peripheral mold portion 91 and the second outer peripheralmold portion 103. The connector mold portion 177 may be integrallyattached to the inner peripheral mold portion 91 or the second outerperipheral mold portion 103, and in this case, the connector moldportion 177 is included in the inner peripheral mold portion 91 or thesecond outer peripheral mold portion 103.

In the assembled state of the mold device 90, the connector terminal 28a and the intake air temperature terminal 23 c are already mounted onthe mold device 90. The mold device 90 has a temporary support portion178 for temporarily supporting the connector terminal 28 a and theintake air temperature terminal 23 c, and the connector terminal 28 aand the intake air temperature terminal 23 c can be temporarily attachedto the temporary support portion 178. The temporary support portion 178is included in, for example, the connector mold portion 177, and theconnector terminals 28 a and the intake air temperature terminal 23 ccan be detachably attached. The temporary support portion 178 cantransition to a support state capable of supporting the terminals 28 aand 23 c and a releasing state for releasing the support of theterminals 28 a and 23 c.

In the mold device 90, the connector terminal 28 a is accommodatedinside the connector mold portion 177, while the intake air temperatureterminal 23 c is in a state of being extended over the connector moldportion 177, the second outer peripheral mold portion 103, and the rootmold portions 105 and 106.

Next, a manufacturing method of the air flow meter 14 will be describedwith reference to FIGS. 36 to 39, and so on, focusing on a procedureafter the housing 21 has been molded with resin.

In the present embodiment, insert molding is performed by resin moldingthe housing in which the connector terminal 28 a and the intake airtemperature terminal 23 c are embedded. In the insert molding, in aprocess of assembling the mold device 90, as shown in FIG. 36, theconnector terminal 28 a and the intake air temperature terminal 23 c aretemporarily attached to the temporary support portion 178 of theconnector mold portion 177. Then, the connector mold portion 177 in thisstate is assembled to the inner peripheral mold portion 91, the outerperipheral mold portions 102, 103, and the like. Thereafter, a moltenresin is injected into the mold device 90, the molten resin is cured tomold the housing 21, and then the mold device 90 is removed from thehousing 21.

In this step, the connector terminal 28 a and the intake air temperatureterminal 23 c are detached from the temporary support portion 178 byshifting the temporary support portion 178 to the released state, andthe connector mold portion 177 is detached from the connector portion 28of the housing 21. In addition, the inner peripheral mold portion 91 andthe outer peripheral mold portions 102 and 103 are also removed from thehousing 21. In the resin-molded housing 21, a part of each of theconnector terminal 28 a and the intake air temperature terminal 23 c isembedded in the housing 21.

Then, as shown in FIG. 37, a step of installing the sensor SA 50 in theinternal space 24 a of the housing 21 is performed. In this step, thesensor SA 50 is inserted into the main body region PC1 of the internalspace 24 a from the housing opening 61, and the sensor SA 50 is pushedin until the circuit step surface 55 of the sensor SA 50 is caught bythe region step surface 66 of the housing 21. With the insertion of thelead terminal 54 into the housing opening 61 from the sensing portion 53of the sensor SA 50, the lead terminal 54 is disposed in the sealingregion PA of the internal space 24 a.

In the mold device 90, the housing 21 is resin-molded so that the entireconnection terminal portion 172 c of the connector terminal 28 a isembedded in the housing 21. For that reason, in the configuration inwhich the inner peripheral surfaces of the main body region PC1 and theconnector region PC2 are molded by the inward portion 93 of the innerperipheral mold portion 91, the main body region PC1 and the connectorregion PC2 can be molded by simply pulling out the inward portion 93from the housing opening 61.

Unlike the present embodiment, for example, in order to resin-mold thehousing 21 in which the connection terminal portion 172 c is separatedfrom the sealing step surface 67 toward the housing opening 61, there isa need to make a part of the inward portion 93 go around between theconnection terminal portion 172 c and the sealing step surface 67. Inthis configuration, since it becomes difficult to remove the inwardportion 93 from the housing opening 61, the housing 21 is not integrallymolded, but multiple members must be assembled together andmanufactured.

As described above, the second terminal portion 172 b and the intake airtemperature terminal portion 175 of the connector terminal 28 a areinstalled in the connector region PC2 so as not to protrude into themain body region PC1. For that reason, when the sensor SA 50 is insertedinto the main body region PC1, the sensor SA 50 is less likely to comeinto contact with the second terminal portion 172 b and the intake airtemperature terminal portion 175. In the main body region PC1, theregion step surface 66 faces the housing opening 61. For that reason,the operator can easily install the sensor SA 50 in the main body regionPC1 so as not to come in contact with the second terminal portion 172 band the intake air temperature terminal portion 175 by inserting thesensor SA 50 aiming at a space between the pair of region step surfaces66.

Thereafter, as shown in FIG. 38, the terminal unit 85 is inserted intothe internal space 24 a from the housing opening 61 and pushed betweenthe lead terminal 54 and the second terminal portion 172 b of theconnector terminal 28 a. In this example, the bridge terminal 86 istemporarily attached to the housing 21 by bringing the bridge terminal86 in contact with the sealing step surface 67.

The operation of joining the bridge terminal 86 to each of the leadterminal 54 and the connector terminal 28 a by welding or the like isperformed using a joining tool such as a welding device having a pair ofwelding electrodes. In this example, a pair of welding electrodes areinserted into the internal space 24 a from the housing opening 61, andthe lead terminal 54 and the first bridge portion 173 a are sandwichedbetween the welding electrodes to perform welding between the leadterminal 54 and the first bridge portion 173 a. With the above joiningoperation, a connection portion between the lead terminal 54 and thebridge terminal 86 is formed. The second terminal portion 172 b and thesecond bridge portion 173 b are welded by sandwiching the secondterminal portion 172 b and the second bridge portion 173 b with a pairof welding electrodes. With the above joining operation, a connectionportion between the connector terminals 28 a and the bridge terminals 86is formed.

In FIG. 39, after the operation of electrically connecting the leadterminal 54 and the connector terminal 28 a through the bridge terminal86 has been completed, a thermosetting resin such as potting resin isinjected from the housing opening 61 into the sealing region PA of theinternal space 24 a. Then, the potting portion 65 is formed by applyinga heat to the thermosetting resin and curing the thermosetting resin. Inthis example, not only the SA main body 170 is covered with thethermosetting resin, but also the lead terminal 54, the bridge terminal86, and the connector terminal 28 a are covered with the thermosettingresin. In this case, the connection portion between the lead terminal 54and the bridge terminal 86 and the connection portion between the bridgeterminal 86 and the connector terminal 28 a are protected by the pottingportion 65.

In the configuration group E, according to the present embodiment, inthe internal space 24 a of the housing 21, the connector terminal 28 adoes not enter between the housing opening 61 and the sensor SA 50 inthe height direction Y. For that reason, after the connector terminal 28a has been attached to the housing 21, the sensor SA 50 can be insertedinto the internal space 24 a through the housing opening 61. Thiseliminates a need for attaching the connector terminal 28 a to thehousing 21 after the sensor SA 50 has been installed in the internalspace 24 a. For that reason, the sensor SA 50 can be inhibited frombeing positionally deviated due to an impact or the like caused by theattachment of the connector terminal 28 a to the housing 21.

In this example, when the positional deviation of the sensor SA 50occurs in the internal space 24 a, the position of the flow ratedetector 22 in the measurement flow channel 32 is also unintentionallydeviated. In this case, the detection accuracy of the flow rate detector22 is likely to be lowered because the amount and speed of the intakeair flowing along the flow rate detector 22 in the measurement flowchannel 32 deviate from design values. On the other hand, according tothe present embodiment, since an unintended positional deviation of thesensor SA 50 is less likely to occur as described above, the detectionaccuracy of the flow rate detector 22 can be inhibited from varying fromproduct to product.

According to the present embodiment, in the internal space 24 a, thesecond terminal portion 172 b of the connector terminal 28 a isaccommodated in the connector region PC2 without protruding into themain body region PC1. For that reason, a configuration can be realizedin which the second terminal portion 172 b is not inserted between thehousing opening 61 and the sensor SA 50 in the height direction Y. Whenthe sensor SA 50 is inserted from the housing opening 61 into the mainbody region PC1, the operator simply prevents the sensor SA 50 fromentering the connector region PC2, thereby being capable of preventingthe sensor SA 50 from coming in contact with the second terminal portion172 b. This makes it possible to inhibit the sensor SA 50 and theconnector terminal 28 a from being damaged or deformed by contactingeach other with the attachment of the sensor SA 50 to the housing 21.

According to the present embodiment, the connector region PC2 isdisposed at a position closer to the housing opening 61 than the SA mainbody 170 of the sensor SA 50. Accordingly, the second terminal portion172 b of the connector terminal 28 a is also disposed at a positioncloser to the housing opening 61 than the SA main body 170. In thatcase, since there is a need to insert a joining tool for joining thesecond terminal portion 172 b and the bridge terminal 86 deeply into theinternal space 24 a, a work load for joining can be reduced. Further, ascompared with a configuration in which the joining tool is inserteddeeply into the internal space 24 a, the SA main body 170 and thehousing 21 can be inhibited from being damaged or deformed due to acontact of the joining tool with the SA main body 170 or the housing 21.

According to the present embodiment, in the internal space 24 a, thesecond terminal portion 172 b of the connector terminal 28 a issupported by the sealing step surface 67 from the side opposite to thehousing opening 61. In this case, when the second terminal portion 172 band the second bridge portion 173 b are joined to each other,unintentional displacement of the second terminal portion 172 b is lesslikely to occur. This makes it possible to inhibit that the secondterminal portion 172 b is relatively displaced with respect to thesecond bridge portion 173 b during the joining operation, which makes itdifficult to properly join the second terminal portion 172 b and thesecond bridge portion 173 b.

According to the present embodiment, the bridge terminal 86 is supportedby the sealing step surface 67 from the side opposite to the housingopening 61. In this case, when the bridge terminal 86 is temporarilyattached to the housing 21, a state in which the bridge terminal 86 isheld in position can be created. For that reason, when the bridgeterminals 86 is joined to the lead terminal 54 and the connectorterminal 28 a, the work load can be reduced by an amount that the workof holding the bridge terminals 86 in position is not required.

According to the present embodiment, on the inner peripheral surface ofthe housing 21, the sealing step surface 67 that supports the secondterminal portion 172 b of the connector terminal 28 a is disposed at aposition closer to the housing opening 61 than the region step surface66 that supports the sensor SA 50. In that case, since the protrusiondimension of the second terminal portion 172 b from the sealing stepsurface 67 becomes as small as possible, the second terminal portion 172b is less likely to be unintentionally deformed when the housing 21 ismolded with resin or the like. In that case, since the joint portionbetween the connector terminal 28 a and the bridge terminal 86 isdisposed between the sealing step surface 67 and the housing opening 61,there is no need to insert the joining tool to a position deeper thanthe sealing step surface 67 in the internal space 24 a. For that reason,the joining operation can be facilitated and the breakage anddeformation of the SA main body 170 and the housing 21 caused by thecontact with the joining tool can be realized.

According to the present embodiment, the second terminal portion 172 bextends from the sealing step surface 67 toward the housing opening 61.In this case, when the second terminal portion 172 b and the secondbridge portion 173 b are sandwiched between the bonding tool such as thewelding electrodes, there is no need to insert the joining tool into theback side of the second terminal portion 172 b and the second bridgeportion 173 b when viewed from the housing opening 61. For that reason,when the second terminal portion 172 b and the second bridge portion 173b are joined together by using the joining tool, the joining operationcan be facilitated.

According to the present embodiment, the connector terminal 28 a istemporarily attached to the temporary support portion 178 of the molddevice 90, so that the housing 21 which is in a state in which theconnector terminal 28 a is embedded is molded with resin. For thatreason, the connector terminal 28 a can be inhibited from beingpositionally deviated with respect to the housing 21.

According to the present embodiment, the sensor SA 50, the connectorterminal 28 a and the bridge terminal 86 are hidden by the thermosettingresin injected into the internal space 24 a from the housing opening 61.For that reason, the positional deviation of the sensor SA 50 and thedeformation or breakage of the lead terminal 54, the connector terminal28 a, and the bridge terminal 86 can be inhibited by the potting portion65 made of the thermosetting resin.

<Configuration Group F>

A configuration group F relating to covering the detection unit will bedescribed with reference to FIGS. 40 to 42 and the like.

As shown in FIGS. 40 and 41, the inner peripheral surface of the lip 89and the inner peripheral surface of the housing body 24 are flush witheach other, and the inner peripheral surface 180 of the sealing regionPA extends straight in the height direction Y from the region stepsurface 66 and the sealing step surface 67 toward the housing opening61. The lip 89 extends along the peripheral portion of the internalspace 24 a to form the housing opening 61, and corresponds to an openrib portion.

As described above, the sealing region PA including the housing opening61 is formed in a rectangular shape as a whole in top view, but fourcorners are curved. In that case, the inner peripheral surface 180 ofthe sealing region PA has a flat inner peripheral flat surface 181extending in the width direction X and the depth direction Z in thehousing opening 61, and an inner peripheral curved surface 182 curved soas to connect the inner peripheral flat surfaces 181 crossing eachother. The inner peripheral curved surface 182 is curved so as to bulgetoward the outer peripheral side so that an acute angle or aright-angled corner portion is not formed in the housing opening 61. Theinner peripheral curved surface 182 corresponds to an inner peripheralcurved surface that is bent so as to bulge toward the outer peripheralside of the sealing region PA.

In the inner peripheral surface 180 of the sealing region PA, the innerperipheral flat surface 181 is disposed at a position corresponding tothe four sides of the housing opening 61, and the inner peripheralcurved surface 182 is disposed at a position corresponding to the fourcorners. Since the inner peripheral flat surface 181 and the innerperipheral curved surface 182 are continuous with each other, no step isformed at the boundary between the inner peripheral flat surface 181 andthe inner peripheral curved surface 182. The inner peripheral flatsurface 181 and the inner peripheral curved surface 182 extend from thehousing opening 61 toward the region step surface 66 and the sealingstep surface 67.

As described above, in the housing 21, the flange portion 27 extendsfrom the housing body 24 in the width direction X and the depthdirection Z, and the ring holding portion 25 is disposed closer to thehousing tip side than the flange portion 27. On the other hand, the lip89 extends from the housing body 24 toward the housing base end side. Inthis case, if the housing attachment is configured to include the ringholding portion 25 and the flange portion 27, the lip 89 is disposed onthe opposite side of the bypass flow channel 30 and the inflow port 33 aacross the housing attachment. In other words, in the height directionY, the housing opening 61 is disposed on the opposite side of the inflowport 33 a across the sensor SA 50.

As described above, the lead terminal 54 of the sensor SA 50 and theconnector terminal 28 a are connected to each other, and the connectionportion 183 is accommodated in the sealing region PA. The connectionportion 183 includes each portion of the lead terminal 54 connected tothe bridge terminals 86, a portion of the connector terminal 28 aconnected to the bridge terminal 86, and the entire bridge terminal 86.The connection portion 183 may include the whole of the second terminalportion 172 b of the connector terminal 28 a (refer to FIG. 34) and thewhole of the lead terminal 54.

Next, a manufacturing method of the air flow meter 14 will be describedfocusing on a procedure for creating the potting portion 65. The pottingportion 65 corresponds to a filling portion.

First, the sensor SA 50 is installed in the internal space 24 a of thehousing 21, and the lead terminals 54 and the connector terminal 28 aare connected to each other with the use of the terminal unit 85. Then,as shown in FIG. 42, a step of injecting the potting material 185, whichis a thermosetting resin, into the internal space 24 a through thehousing opening 61 is performed so that the potting material 185 doesnot overflow from the internal space 24 a. In this injection step, theinternal space 24 a is sealed by filling the internal space 24 a with aliquid or fluid potting material 185. In this example, the pottingmaterial 185 may also be referred to as a sealing material. In thepresent embodiment, for example, epoxy resin is used as the pottingmaterial 185, and the potting material 185 corresponds to a filler.

The potting material 185 corresponds to a potting resin and a curableresin. As the potting material 185, a urethane resin or a silicone resinmay be used. When the urethane resin or the silicone resin is used asthe potting material 185, the potting portion 65 tends to be softer thanwhen the epoxy resin is used as the potting material 185.

In this injection step, an injection operation is performed so that amass of air such as a void or a gap is not formed in the pottingmaterial 185 filled in the sealing region PA. In this example, in thesealing region PA, an acute angle or a right-angled inward portion doesnot exist due to the inner circumference curved surface 182. In thiscase, a gap is less likely to occur between the potting material 185 andthe inner peripheral surface 180 of the sealing region PA, and aphenomenon that the potting material 185 creeps up toward the housingopening 61 along the inner peripheral surface 180 of the sealing regionPA is less likely to occur.

In the injecting step, the potting material 185 is filled in the sealingregion PA so that the sensor SA 50, the connection portion 183, and theconnector terminal 28 a are hidden from the housing opening 61. In thisexample, in the inner peripheral surface 180 of the sealing region PA,it is considered that the creep-up phenomenon occurs somewhat even ifthe creep-up phenomenon of the potting material 185 is less likely tooccur due to the inner curved surface 182. Therefore, the injectionamount of the potting material 185 is set so that the center portion ofthe surface of the potting material 185 is positioned slightly inwardfrom the housing opening 61 so that the potting material 185 does notoverflow from the housing opening 61 even if the creep-up phenomenonoccurs.

In the internal space 24 a, the connection portion between the leadterminal 54 and the intake air temperature terminal 23 c is also coveredwith the potting material 185. The connection portion between the leadterminal 54 and the intake air temperature terminal 23 c includes aconnection portion between the lead terminal 54 and the bridge terminal86 in the intake air temperature terminal 23 c, and the entire bridgeterminal 86.

After the potting material 185 has been injected, the potting material185 is heated and cured to form the potting portion 65. In this example,the hardness and the like of the potting portion 65 differ depending onthe component and the like of the type of the potting material 185.Regardless of the hardness of the potting portion 65, the pottingportion 65 can inhibit the occurrence of positional deviation of thesensor SA 50 in the internal space 24 a, but as the potting portion 65is harder, the inhibiting effect against the positional deviation of thesensor SA 50 is higher. In addition, the potting portion 65 is softer,the potting portion 65 more easily adheres to the sealing region PA, thesensor SA 50, and the connection portion 183, so that the sealingproperty of the potting portion 65 can be enhanced.

The potting portion 65 covers the sensor SA 50 from the housing opening61, and corresponds to the cover portion. In that case, the pottingportion 65 covers the connection portion between the lead terminal 54and the connector terminal 28 a from the housing opening 61 side. Thepotting material 185 corresponds to a covering material.

In the configuration group F, according to the present embodiment, sincethe potting portion 65 is formed by injecting the potting material 185into the internal space 24 a, a pressure is less likely to be applied tothe internal space 24 a when the internal space 24 a is sealed. In thiscase, since the positional deviation of the sensor SA 50 is inhibitedfrom being unintentionally generated by the pressure applied to theinternal space 24 a, the positional deviation of the sensor SA 50 isless likely to be generated from product to product. Therefore, thedetection accuracy of the flow rate detector 22 can be inhibited fromvarying from product to product.

According to the present embodiment, the housing opening 61 is definedby the lip 89 protruding from the housing body 24. For that reason, thedepth dimensions of the internal space 24 a and the sealing region PA inthe height direction Y can be changed by simply changing the protrusiondimension of the lip 89 without changing the shape or size of thehousing body 24. In this instance, the depth dimensions of the internalspace 24 a and the sealing region PA can be appropriately set inaccordance with the length dimension of the sensor SA 50 in the heightdirection Y without decreasing the versatility of the housing body 24.This makes it possible to avoid that the sensor SA 50 is too longrelative to the internal space 24 a and a part of the sensor SA 50protrudes from the potting material 185 even though the internal space24 a is sealed by the potting material 185.

According to the present embodiment, the inner peripheral curved surface182 is included in the inner peripheral surface 180 of the sealingregion PA. This makes it possible to inhibit a gap from being generatedbetween the potting material 185 and the inner peripheral surface 180,or the potting material 185 from creeping up along the inner peripheralsurface 180 and overflowing from the housing opening 61. Therefore, thesealing performance of the internal space 24 a by the potting material185 can be appropriately exhibited.

According to the present embodiment, in the air flow meter 14, thehousing opening 61 is disposed on the opposite side to the inflow port33 a across the ring holding portion 25. For that reason, aconfiguration can be realized in which the housing opening 61 isdisposed outside the intake pipe 12 a instead of the intake passage 12.In this case, since the potting portion 65 is not always exposed to theintake air flowing through the intake passage 12, damage ordeterioration of the potting portion 65 can be inhibited. As a result,the sealing performance of the internal space 24 a by the pottingportion 65 can be exhibited for a long period of time.

According to the present embodiment, in the internal space 24 a, theconnection portion 183 between the lead terminal 54 and the connectorterminal 28 a is covered with the potting portion 65 in addition to thesensor SA 50. For that reason, not only the sensor SA 50 but also theconnection portion 183 can be protected by the sealing performance ofthe potting portion 65.

<Configuration Group G>

A configuration group G relating to an information portion will bedescribed with reference to FIG. 43 and the like.

As shown in FIG. 43, in the housing 21, when one end face is referred toas a housing tip end face 191 and the other end face is referred to as ahousing base end face 192, the housing opening 61 is provided in thehousing base end face 192. The housing base end face 192 is formed bythe outer peripheral surfaces of the housing body 24, the flange portion27, and the connector portion 28, and the housing opening 61 is disposedin the outer peripheral surface of the housing body 24. The housing baseend face 192 is provided with the multiple thinned portions 41 and thescrew holes 42 in addition to the housing opening 61, and the thinnedportions 41 and the screw holes 42 are disposed in the outer peripheralsurface of the flange portion 27. The housing base end face 192corresponds to a housing face which is one surface of the housing.Further, the housing tip end face 191 and the housing base end face 192are aligned in the height direction Y.

The housing opening 61 is an open end portion of the internal space 24a, and as described above, the internal space 24 a is sealed from thehousing opening 61 side by the potting portion 65. In the pottingportion 65, a potting surface 193, which is an outer surface thereof,faces a side opposite to the sensor SA 50 in the height direction Y likethe housing base end face 192. Further, as described above, the pottingmaterial 185 filled in the internal space 24 a creeps up the innerperipheral surface 180 of the sealing region PA, so that the peripheralportion of the potting surface 193 is easily curved. However, most ofthe potting surface 193 is flat surface except for the peripheralportion. In this case, the potting portion 65 corresponds to a sealingportion, and the potting surface 193 corresponds to an outer surface ofthe sealing portion.

In the housing 21, the housing opening 61 is disposed on the sideopposed to the inflow port 33 a across the sensor SA 50 in the heightdirection Y. In this case, the inflow port 33 a is disposed inside theintake pipe 12 a in the intake passage 12, while the potting portion 65is disposed outside the intake pipe 12 a. In the potting portion 65, thepotting surface 193 faces a side opposite to the intake pipe 12 a in theheight direction Y.

As described above, the housing opening 61 is formed in a rectangularshape as a whole. In this case, the housing opening 61 has a pair offirst side portions 195, which are long sides, and a pair of second sideportions 196, which are short sides, and has a flat shape extending inthe depth direction Z as a whole. In this case, the first side portions195 extend in the depth direction Z, and the second side portions 196extend in the width direction X. The housing opening 61 is chamfered atfour corners, and the chamfered portions are curved toward the outerperipheral side in a state in which the first side portions 195 and thesecond side portions 196 are connected to each other. The first sideportions 195 correspond to opposite sides. Also, the chamfered portionsmay extend straight, rather than curved, or may be bent. The chamferedportions may not be disposed at all four corners of the housing opening61.

The potting surface 193 is provided with an information portion 194indicating predetermined information determined in advance. Theinformation portion 194 has numbers, characters, marks, and the like,the marks include symbols, logos, storing marks, and the like, and thestorage marks include two-dimensional codes and the like. Various typesof information are stored in the storage marks, and the various types ofinformation include correction values used for correction of detectionsignals of the flow rate detector 22, the intake air temperature sensor23, and the like when the detection signals are corrected by the circuitchip 81 or the ECU 20. In addition to the correction values, the varioustypes of information include a characteristic map indicating thecharacteristics of the flow rate detector 22, the intake air temperaturesensor 23, the air cleaner 19, and the like.

The information portion 194 is formed of ink, paint, and unevennessapplied to the potting surface 193. As a method of applying theinformation portion 194 to the potting surface 193, laser marking, inkmarking, or the like can be given. The information portion 194 has anumber string or a character string formed by multiple numbers orcharacters to indicate various information, and the number strings orthe character strings are aligned along the first side portions 195. Inthis case, since the user or the like only needs to read the informationdisplayed by the information portion 194 along the first side portion195, the content of the information portion 194 is hardly erroneouslyread. The information portion 194 is arranged in a wide range of thepotting surface 193, but is basically arranged in a flat portion of thepotting surface 193.

In the configuration group G, according to the present embodiment, sincethe potting portion 65 is formed by injecting the potting material 185into the internal space 24 a, most of the potting surface 193 can beflattened. In addition, since the housing opening 61 and the internalspace 24 a are large enough to allow the sensor SA 50 to be insertedinto the housing opening 61 and the internal space 24 a, the pottingsurface 193 is less likely to be insufficient for displaying theinformation portion 194. In this manner, since the potting surface 193is flattened and enlarged, the visibility of the information portion 194imparted to the potting surface 193 can be enhanced.

According to the present embodiment, in the internal space 24 a of thehousing 21, the SA main body 170 of the sensor SA 50 and the connectorterminals 28 a are aligned laterally in the width direction X. For thatreason, the width dimension of the internal space 24 a and the widthdimension of the housing opening 61 are increased in the width directionX to such an extent that the SA main body 170 and the connectorterminals 28 a can be aligned laterally. In other words, the widthdimension of the potting surface 193 increases in the width direction X.In that case, since the size of the information portion 194 can beenlarged on the potting surface 193, the visibility of the informationportion 194 can be enhanced.

According to the present embodiment, since the housing opening 61 isdisposed on the side opposed to the inflow port 33 a across the sensorSA 50 in the height direction Y, the potting surface 193 is disposedoutside the intake pipe 12 a. In that case, the operator can visuallyrecognize the potting surface 193 and the information portion 194 whilethe air flow meter 14 is attached to the intake pipe 12 a. Therefore,when visually recognizing the information portion 194, a labor ofdetaching the air flow meter 14 from the intake pipe 12 a can be saved.

According to the present embodiment, since the housing opening 61 isflattened as a whole so that the pair of first side portions 195 arelong sides, the alignment direction of the information portions 194 canbe clarified. In this case, since the number string and the characterstring of the information portion 194 are aligned along the first sideportions 195 on the potting surface 193, the operator can be inhibitedfrom reading the number string and the character string incorrectly. Inthis manner, the visibility of the information portion 194 can beenhanced by the shape of the potting surface 193.

According to the present embodiment, the housing base end face 192 isprovided with the thinned portions 41. In this example, if an attempt ismade to secure a flat surface on the housing base end face 192 which islarge enough not to cause insufficient visibility of the informationportion 194, there is a fear that the thinned portions 41 on the housingbase end face 192 will be insufficient. If there is a shortage of thethinned portions 41 at the housing base end face 192, there is a fearthat the housing 21 is thickened, and the unintentional deformation ofthe housing 21 may occur due to curing of the molten resin when thehousing 21 is molded with resin. On the other hand, in the presentembodiment, since the information portion 194 is provided to the pottingsurface 193, there is no need to secure a flat surface suitable fordisplay of the information portion 194 on the housing base end face 192.In this case, the sufficient thinned portions 41 is disposed on thehousing base end face 192, so that deformation of the housing 21 due toresin molding can be inhibited, and visibility of the informationportion 194 on the potting surface 193 can be enhanced.

According to the present embodiment, the sensor SA 50 is covered withthe potting portion 65 in the internal space 24 a of the housing 21. Inthis example, unlike the present embodiment, for example, in aconfiguration in which a lid member resin molded as a separate memberfrom the housing 21 is attached to the housing opening 61, as thehousing opening 61 is larger in size, the lid member becomes larger insize. When the lid member is increased in size, it is considered thatthe lid member needs to be formed to be thick enough so that the lidmember can retain its own shape, and on the other hand, it is alsoconsidered that there is a need to form a thinned portion in the lidmember so as not to cause deformation due to resin molding. This makesit difficult for the lid member to secure a flat surface to the extentthat the information portion 194 can be provided.

On the other hand, according to the present embodiment, there is no needto form the thinned portions 41 in the potting portion 65 to which theinformation portion 194 is given because the resin molding is notperformed. In addition, with the utilization of the phenomenon that thepotting surface 193 is inevitably flattened with respect to the pottingportion 65 filled in the internal space 24 a, the information portion194 can be disposed almost entirely on the potting surface 193.Therefore, the visibility of the information portion 194 can be enhancedon the potting surface 193.

<Configuration Group H>

A configuration group H related to correcting the detection result ofthe physical quantity detector will be described with reference to FIGS.44 to 57 and the like.

As shown in FIG. 44, the air flow meter 14 has an inward part 501 whichenters the inside of the intake pipe 12 a, and an outward part 502 whichprotrudes to the outside of the intake pipe 12 a without entering theinside of the intake pipe 12 a. The inward part 501 includes the bypassflow channel 30 and the ring holding portion 25, and the outward part502 includes the housing opening 61, the flange portion 27, and theconnector portion 28. The inward part 501 and the outward part 502 arealigned in the height direction Y to divide the air flow meter 14 intotwo portions, and a boundary of those parts 501 and 502 coincide withthe open end of the pipe flange 12 c. The housing body 24 and the sensorSA 50 extend across a boundary between the inward part 501 and theoutward part 502 in the height direction Y.

In the air flow meter 14, the outward part 502 includes the housing baseend face 192, and the inward part 501 includes the housing tip end face191. In this case, in the housing 21, the housing base end face 192 maybe referred to as the end on the side of the outward part 502, and thehousing tip end face 191 may be referred to as the end on the side ofthe inward part 501. In addition, the inward part 501 and the outwardpart 502 are aligned in the height direction Y, and the height directionY corresponds to a direction in which the inward part 501 and theoutward part 502 are aligned.

The air flow meter 14 has temperature detectors 505 and 506 fordetecting the temperature of intake air flowing through the intakepassage 12, in addition to the flow rate detector 22. The temperaturedetectors 505 and 506 are sensors configured to include elements such astemperature detection elements mounted on a circuit board, and detect aninternal temperature of the intake pipe 12 a.

The first temperature detector 505 is provided in the measurement flowchannel 32, and detects a temperature of the intake air in themeasurement flow channel 32. The first temperature detector 505 detectsthe temperature of the intake air flowing in the intake passage 12 bydetecting the temperature of the intake air flowing in the measurementflow channel 32. The first temperature detector 505 is disposed in thesensing portion 53 of the sensor SA 50, and specifically, the firsttemperature detector 505 is mounted on the detection board 22 a togetherwith the detection element 22 b. In this case, the detection board 22 acorresponds to a circuit board on which the elements of the firsttemperature detector 505 are mounted.

The second temperature detector 506 is disposed at a position closer tothe housing opening 61 than the first temperature detector 505 in theheight direction Y, and detects the internal temperature of the air flowmeter 14. The second temperature detector 506 detects the internaltemperature of the intake pipe 12 a by detecting the internaltemperature of the air flow meter 14 even if the second temperaturedetector 506 is disposed at a position where the second temperaturedetector 506 does not touch the intake air. The second temperaturedetector 506 is disposed between the housing base end face 192 and thefirst temperature detector 505 in the height direction Y by beingdisposed at a position closer to the housing opening 61 than themeasurement flow channel 32. The second temperature detector 506 isdisposed in the circuit accommodation portion 51 of the sensor SA 50,and specifically, the second temperature detector 506 is mounted on thelead frame 82 together with the circuit chip 81. In this case, the leadframe 82 corresponds to a circuit board on which the elements of thesecond temperature detector 506 are mounted.

In the internal space 24 a of the housing 21, the first temperaturedetector 505 is disposed in the sealing region PA (refer to FIG. 8, andso on), and the second temperature detector 506 is disposed in the openregion PB (refer to FIG. 8, and so on).

In this example, the internal combustion engine 11 or the like thatgenerates a heat outside the intake pipe 12 a is referred to as anexternal heat source, and it is assumed that the heat is applied fromthe external heat source to the air flow meter 14. In the air flow meter14, it is considered that the heat from the external heat source isfirst applied to the outward part 502, and the heat is transferred fromthe outward part 502 to the inward part 501. In this case, since theheat from the external heat source is applied to the temperaturedetectors 505 and 506 in addition to the heat from the intake air, anerror is likely to occur between the detected value, which is thedetection result of the temperature detectors 505 and 506, and an actualtemperature of the intake air flowing through the intake passage 12.Hereinafter, the actual temperature of the intake air flowing throughthe intake passage 12 is also referred to as an actual temperature ofthe intake air. The actual temperature may also be referred to as asteady value.

As described above, the first temperature detector 505 is disposed at aposition farther from the outward part 502 than the second temperaturedetector 506. In addition, while the second temperature detector 506 isdisposed at a position of hardly touching the intake air, the firsttemperature detector 505 is disposed at a position of easily touchingthe intake air in the measurement flow channel 32. Due to the abovefactors, the detected value of the first temperature detector 505 isless susceptible to the influence of the external heat source than thedetected value of the second temperature detector 506, and tends to be avalue close to the actual temperature of the intake air. In other words,the error of the first temperature detector 505 with respect to theactual temperature of the intake air is likely to be smaller than theerror of the second temperature detector 506 with respect to the actualtemperature of the intake air.

The circuit chip 81 according to the present embodiment performs aprocess of acquiring a temperature correction value obtained bycorrecting the detected value of the first temperature detector 505 as atemperature measurement value. The circuit chip 81 corresponds to ameasurement control device that controls the air flow meter 14, such asacquiring a temperature correction value as a measured value. Like theECU 20, the circuit chip 81 is an arithmetic processing circuitincluding a processor, a RAM, a storage medium such as a ROM and a flashmemory, a microcomputer including an input and output unit, a powersupply circuit, and the like. The circuit chip 81 is electricallyconnected to the flow rate detector 22, the intake air temperaturesensor 23, and the temperature detectors 505 and 506, and the detectionsignals of the detectors 22, 505, and 506 and the sensor 23 are input tothe circuit chip 81. The circuit chip 81 measures the flow rate and thetemperature of the intake air flowing through the measurement flowchannel 32 with the use of the detection signals of the detectors 22,505, 506 and the sensor 23.

As shown in FIG. 45, the multiple connector terminals 28 a of the airflow meter 14 include a signal terminal 521, a power supply terminal522, a ground terminal 523, and an adjustment terminal 524. Each of theterminals 521 to 524 is electrically connected to the circuit chip 81,and the circuit chip 81 outputs measured values of temperatures and flowrates from the signal terminal 521 to the ECU 20 or the like. In thisexample, the circuit chip 81 stores the information on the temperaturecorrection value in the storage medium in association with timeinformation such as correction timing. The adjustment terminal 524 canbe connected with an adjustment device as an external device capable ofadjusting the correction accuracy by the circuit chip 81. In a statewhere the adjustment device is electrically connected to the adjustmentterminal 524, the information on the temperature correction value storedin the storage medium can be rewritten.

The circuit chip 81 includes a temperature correction unit 510 thatacquires a temperature correction value by correcting the detected valueof the first temperature detector 505. As shown in FIG. 46, thetemperature correction unit 510 includes multiple functional blocks suchas a first correction unit 511, a temperature differential unit 512, asecond correction unit 513, a characteristic transformation unit 514, acorrection amount calculation unit 515, and a correction valuecalculation unit 516. In the temperature correction unit 510corresponding to the physical quantity correction unit, the detectionresults of the flow rate detector 22 and the temperature detectors 505and 506 are input to the first correction unit 511, the temperaturedifferential unit 512, and the characteristic transformation unit 514.In the temperature correction unit 510, the detected value of the flowrate and the detected value of the temperature are acquired based on thedetection signals of the flow rate detector 22 and the temperaturedetectors 505 and 506.

In the present embodiment, the first temperature signal Sa1 is correctedwith the use of a first temperature signal Sa1 including the detectedvalue of the first temperature detector 505, a second temperature signalSa2 including the detected value of the second temperature detector 506,and a flow rate signal Sa3 including the detected value of the flow ratedetector 22. In the temperature correction unit 510, the firsttemperature signal Sa1 is input to the first correction unit 511 and thetemperature differential unit 512, the second temperature signal Sa2 isinput to the temperature differential unit 512, and the flow rate signalSa3 is input to the characteristic transformation unit 514.

The first temperature detector 505 corresponds to a physical quantitydetector that detects a physical quantity called a temperature, and thefirst temperature signals Sa1 correspond to detection results of thephysical quantity detector. The second temperature detector 506corresponds to a same kind-quantity detector that detects a temperaturehaving the same kind of physical quantity as the first temperaturedetector 505, and the second temperature signal Sa2 corresponds todetection results of the same kind-quantity detector. The flow ratedetector 22 corresponds to a different kind-quantity detector thatdetects a flow rate which is a physical quantity of a different typefrom that of the first temperature detector 505, and the flow ratesignals Sa3 correspond to detection results of the differentkind-quantity detector. The second temperature signal Sa2 and the flowrate signal Sa3 correspond to correction parameters used for correctionof the first temperature signal Sa1.

The first correction unit 511 calculates a first correction signal Sb1by performing response correction of the first temperature signal Sa1.The temperature differential unit 512 calculates a difference, which isa difference between the first temperature signal Sa1 and the secondtemperature signal Sa2, as a temperature differential signal Sb2. Thesecond correction unit 513 calculates a differential correction signalSb3 by performing response correction of the temperature differentialsignal Sb2. The characteristic transformation unit 514 calculates a flowrate transformation signal sb4 by performing characteristictransformation of the flow rate signal Sa3. The correction amountcalculation unit 515 calculates a correction amount signal Sb5 with theuse of the differential correction signal Sb3 and the flow ratetransformation signal sb4. The correction value calculation unit 516calculates a correction value signal Sc with the use of the firstcorrection signal Sb1 and the correction amount signal Sb5.

The first correction unit 511 corrects the first temperature signal Sa1based on a behavior of change of the first temperature signal Sa1, andacquires the correction value as the first correction signal Sb1. Inthis case, the first correction unit 511 corresponds to a changecorrection unit. In this example, a first-order delay correction isperformed on the first temperature signal Sa1 as shown in FIG. 47 toobtain the first correction signal Sb1. For example, in the firsttemperature signal Sa1, a detected value Sa1 (tn) at a timing tn, a pastslope m, and a time constant A are acquired, and the detected value Sa1(tn) is added to the multiplication of the slope m and the time constantA, thereby calculating the correction value Sb1 (tn) at the timing tn.In this manner, the first correction signal Sb1 is acquired bycalculating the respective correction values Sb1 (tn) with the use ofthe following (Expression 1).

Sb1(tn)=Sa1(tn)+m×A  (Ex. 1)

In (Ex. 1), the slope m is calculated by dividing an amount of changeΔSa1 of the first temperature signal Sa1 in a minute time Δt by theminute time Δt. For example, the minute time Δt is calculated fortimings tn and tn−1, and an amount of change ΔSa1 is calculated with theuse of the detected values Sa1 (tn) and Sa1 (tn−1) at the timings tn andtn−1.

The time constant A is set in accordance with a flow rate of intake airin the intake passage 12. For example, as shown in FIG. 48, the timeconstant A is set to a larger value as the flow rate signal Sa3 issmaller. Information indicating a relation between the flow rate signalSa3 and the time constant A is stored as flow time information such as amap, data, and a mathematical expression in the storage medium of thecircuit chip 81. The first correction unit 511 reads the flow timeinformation from the storage medium or the like, and calculates the timeconstant A corresponding to the flow rate signal Sa3 with the use of theflow time information or the like. In this instance, the firstcorrection unit 511 corrects the first temperature signal Sa1 with theuse of a flow rate which is a physical quantity of a kind different fromthe temperature, and corresponds to a different king-quantity correctionunit.

The first temperature signal Sa1 converges to a convergence valuecorresponding to the actual temperature of the intake air and stabilizesat a convergence value even if the first temperature signal Sa1 is notcorrected based on the behavior of change of the first temperaturesignal Sa1. As the flow rate of the intake air in the intake passage 12increases more, the heat imparted to the air flow meter 14 from theexternal heat source is more likely to be released in the intake passage12, the first temperature signal Sa1 is more likely to converge to theconvergence value, and the response of the first temperature signal Sa1becomes higher. For that reason, as shown in FIG. 49, when the flow rateof the intake air in the intake passage 12 is relatively large, thefirst correction signal Sb1 tends to converge to the convergence valueeven if the correction amount is relatively small. On the other hand, ifthe flow rate of the intake air in the intake passage 12 is relativelysmall, there is a need to relatively increase the correction amount inorder to converge the first correction signal Sb1 to the convergencevalue. Therefore, as described above, it is preferable to set the timeconstant A to a larger value as the flow rate of the flow rate signalSa3 and the like is smaller. The time constant A corresponds to a flowrate correction amount.

The response of the first correction signal Sb1 is enhanced bycompensating the response of the first temperature signal Sa1 with theuse of the behavior of change as the temporal change informationincluded in the first temperature signal Sa1. As shown in FIG. 50, atime Tb required for the first correction signal Sb1 to reach a firstconvergence value Ev1, which is the convergence value for the firsttemperature signal Sa1, is shorter than the time Tb required for thefirst temperature signal Sa1 to reach the first convergence value Ev1.For example, when the first temperature signal Sa1 and the firstcorrection signal Sb1 start to change at the timing t0 in accordancewith a change in the actual temperature of the intake air, the firsttemperature signal Sa1 reaches the first convergence value Ev1 at atiming t2. On the other hand, the first correction signal Sb1 reachesthe first convergence value Ev1 at a timing t1 earlier than the timingt2. As described above, the first correction signal Sb1 is higher inresponse than the first temperature signal Sa1. In other words, when theactual temperature of the intake air starts to change, the firstcorrection signal Sb1 is smaller than the first temperature signal Sa1in the error from the first convergence value Ev1, which means that theaccuracy of the first correction signal Sb1 is higher. This is becausethe first correction unit 511 sets the time constant A to be larger asthe flow rate signal Sa3 is smaller in a transient time of the actualtemperature.

In this example, when the heat is applied to the air flow meter 14 fromthe external heat source, an error between the actual temperature andthe first temperature signal Sa1 becomes larger, and in addition, theresponse of the first temperature signal Sa1 when the actual temperatureof the intake air changes tends to decrease. This is because it isconsidered that the heat from the external heat source is transmittedfrom the housing 21 to the first temperature detector 505 through themold portion 76 of the sensor SA 50 and the intake air in themeasurement flow channel 32. On the other hand, even if the response ofthe first temperature signal Sa1 is lowered by the heat from theexternal heat source, the response of the first correction signal Sb1 isenhanced by the first correction unit 511.

When the response of the first correction signal Sb1 is increased more,the response of the correction value signal Sc is increased more. Inthis example, the correction value signal Sc is output from the circuitchip 81 to the ECU 20 as information on the temperature of the intakeair, and the correction value signal Sc is used by the ECU 20 to controlthe combustion system 10. For that reason, if the response of thecorrection value signal Sc is enhanced, an improvement in fuelefficiency and emission can be realized, and erroneous diagnosis of afailure diagnosis device such as an OBD (On-board diagnostics) can beinhibited.

The temperature differential unit 512 calculates the temperaturedifferential signal Sb2 based on one of the first temperature signal Sa1and the second temperature signal Sa2. The temperature differential unit512 of the present embodiment uses the first temperature signal Sa1 as areference, and as shown in FIG. 51, uses a value obtained by subtractingthe first temperature signal Sa1 from the second temperature signal Sa2as the temperature differential signal Sb2. In FIG. 51, the secondconvergence value Ev2, which is the convergence value for the secondtemperature signal Sa2, is larger than the first convergence value Ev1.As described above, a case in which the second convergence value Ev2 islarger than the first convergence value Ev1 includes a case in which theheat applied to the first temperature detector 505 from the externalheat source is larger than the heat applied to the first temperaturedetector 505 from the intake air flowing through the measurement flowchannel 32.

When the response of the second temperature signal Sa2 is higher thanthe response of the first temperature signal Sa1, as shown in FIG. 52,the temperature differential signal Sb2 gradually increases, andeventually reaches a neighborhood difference ΔEv, which is a differencebetween the first convergence value Ev1 and the second convergence valueEv2. In this example, because an error between the first temperaturesignal Sa1 and the first convergence value Ev1 is larger than an errorbetween the second temperature signal Sa2 and the second convergencevalue Ev2, the temperature differential signal Sb2 gradually increasestoward the neighborhood difference ΔEv with the first temperature signalSa1 as a reference.

The second correction unit 513 corrects the temperature differentialsignal Sb2 based on a behavior of change of the temperature differentialsignal Sb2, and acquires a correction value as the differentialcorrection signal Sb3. The second correction unit 513 performs thefirst-order delay correction with the use of the present value and thepast value, similarly to the first correction unit 511, for example, forthe temperature differential signals Sb2. As a result, the response ofthe differential correction signal Sb3 is higher than the response ofthe temperature differential signal Sb2. Specifically, as shown in FIG.52, a time required for the differential correction signal Sb3 to reachthe neighborhood difference ΔEv is shorter than a time required for thetemperature differential signal Sb2 to reach the neighborhood differenceΔEv. This is because, as shown in FIG. 53, the second correction unit513 sets the differential correction amount of the correction amountsignal Sb5 or the like to a larger value as the temperature differentialsignal Sb2 becomes larger at the transient time of the actualtemperature.

Information indicating the relation between the temperature differentialsignal Sb2 and the differential correction signal Sb3 is stored astemperature compensation information such as a map, data, and amathematical expression in the storage medium of the circuit chip 81.The second correction unit 513 reads the temperature compensationinformation from the storage medium or the like, and calculates thedifferential correction signal Sb3 corresponding to the temperaturedifferential signal Sb2 with the use of the temperature compensationinformation or the like. In this instance, the second correction unit513 corresponds to a differential correction unit, and the differentialcorrection signal Sb3 corresponds to a differential correction amount.

As described above, after calculating the difference between the firsttemperature signal Sa1 and the second temperature signal Sa2, thetemperature correction unit 510 calculates the differential correctionsignal Sb3 by performing the response correction of the difference. Onthe other hand, unlike the present embodiment, a configuration isconceivable in which the difference between the first correction signalSb1 and the second temperature signal rather than the first temperaturesignal Sa1 is calculated as a differential correction signal Sx. In theabove configuration, as shown in FIGS. 54 and 55, the differentialcorrection signal Sx reaches the neighborhood difference ΔEv with agradual decrease after the differential correction signal Sx oncebecomes larger than the neighborhood difference ΔEv. In other words, inthe differential correction signal Sx, an overshoot occurs at an initialstage of the response. As described above, when the differentialcorrection signal Sx includes an overshoot, the correction value signalalso includes an overshoot. When it is assumed that the correction valuesignal is used for controlling the combustion system 10 in the ECU 20,there are concerns that the fuel efficiency and the emission arelowered, and that the diagnostic accuracy of the failure diagnosisdevice is lowered.

The time information of the differential correction signal Sb3 acquiredby the second correction unit 513 matches the time information of thefirst correction signal Sb1 acquired by the first correction unit 511.For example, in the first correction unit 511, the temperaturedifferential unit 512, and the second correction unit 513, variousprocesses are performed on the first temperature signal Sa1, the secondtemperature signal Sa2, and the temperature differential signal Sb2, asa result of which some response delay occurs. On the other hand, theresponse delay time generated in the first correction unit 511 is thesame as the total time of the response delay times generated in thetemperature differential unit 512 and the second correction unit 513. Inthis instance, the first correction signal Sb1 and the differentialcorrection signal Sb3 included in the correction value signal Sc havethe same time information, and the measurement accuracy of thecorrection value signal Sc is improved as compared with, for example, aconfiguration in which the first correction signal Sb1 and thedifferential correction signal Sb3 have different time information.

The time information of the first correction signal Sb1 and the timeinformation of the differential correction signal Sb3 may not coincidewith each other. Even in this case, if the deviation of the timeinformation is a slight deviation amount such as being included in anappropriate range, the measurement accuracy of the correction valuesignal Sc is kept in an appropriate range, and the measurement accuracyis inhibited from being remarkably lowered.

The characteristic transformation unit 514 performs characteristictransformation of the flow rate signal Sa3 so that the content of theflow rate signal Sa3 is reflected in the response correction in thefirst correction unit 511 and so that the content of the flow ratesignal Sa3 is reflected in the response correction in the secondcorrection unit 513, and calculates the flow rate transformation signalsb4. The characteristic transformation unit 514 is connected to each ofthe first correction unit 511 and the second correction unit 513, andoutputs the flow rate transformation signal Sb4 to the correction units511 and 513. For example, the flow rate transformation signal sb4converts the flow rate signal Sa3 into a mode that is easily applied tothe first temperature signal Sa1 or the flow time information as shownin FIG. 48.

The correction amount calculation unit 515 acquires, as the correctionamount signal Sb5, a multiplied signal obtained by multiplying thedifferential correction signal Sb3 by the flow rate transformationsignal sb4. In this instance, the correction amount calculation unit 515calculates, as the correction amount signal Sb5, a value obtained byincreasing or decreasing the differential correction signal Sb3 inaccordance with the flow rate of the intake air in the measurement flowchannel 32.

The correction value calculation unit 516 acquires an integrated signalobtained by adding the first correction signal Sb1 and the correctionamount signal Sb5 as the correction value signal Sc. In this instance,the correction value calculation unit 516 calculates, as the correctionvalue signal Sc, a value obtained by increasing or decreasing the firstcorrection signal Sb1 in accordance with both the temperature differencebetween the first temperature detector 505 and the second temperaturedetector 506 and the flow rate of the intake air in the measurement flowchannel 32. The correction value signal Sc may also be referred to as atemperature correction value or a temperature measurement value.

As shown in FIGS. 56 and 57, a correction convergence value Ev3, whichis the convergence value for the correction value signal Sc, is closerto the actual temperature Sd of the intake air than the firstconvergence value Ev1 for the first temperature signal Sa1. In thisinstance, an error between the correction value signal Sc and the actualtemperature signal Sd is a difference between the correction convergencevalue Ev3 and the actual temperature Sd, and is smaller than adifference between the first convergence value Ev1 and the actualtemperature Sd. Moreover, the time required for the correction valuesignal Sc to reach the correction convergence value Ev3 is the same asthe time Tb required for the first correction signal Sb1 to reach thefirst convergence value Ev1. Therefore, the correction value signal Scis higher in both the measurement accuracy and the response than thefirst temperature signal Sa1.

The circuit chip 81 has a function of executing processing of eachfunctional block of the temperature correction unit 510. In this case,the function of executing the processing of the temperature correctionunit 510 corresponds to a physical quantity correction unit, thefunction of executing the processing of the first correction unit 511corresponds to a change correction unit and the different king-quantitycorrection unit, and the function of executing the processing of thesecond correction unit 513 corresponds to a differential correctionunit.

The circuit chip 81 has a flow rate correction unit as a function ofimproving the measurement accuracy of the flow rate correction values bycorrecting the flow rate signals Sa3 of the flow rate detector 22. Theflow rate correction unit is electrically connected to the intake airtemperature sensor 23, and acquires a detection signal of the intake airtemperature sensor 23. The flow rate correction unit uses the detectionsignal of the intake air temperature sensor 23 as a correction parameterfor correction of the flow rate signal Sa3. In this example, since theintake air temperature sensor 23 is provided outside the housing 21, thedegree of heat application from the external heat source is likely to besmaller than that of the flow rate detector 22. This is because, sincethe intake air temperature sensor 23 is exposed to the intake passage12, a heat is likely to be applied to the intake air temperature sensor23 from the intake air flowing through the intake air passage 12, whilethe heat applied to the housing 21 from an external heat source is lesslikely to be transmitted to the intake air temperature sensor 23. Forthat reason, the correction of the flow rate signal Sa3 is performedwith the use of the detection signal of the intake air temperaturesensor 23, which is less affected by the heat from the external heatsource, as a correction parameter, so that the correction accuracy canbe improved.

In the configuration group H, according to the present embodiment, thesecond temperature detector 506 is disposed between the housing base endface 192 and the first temperature detector 505 in the height directionY. In that case, the degree of heat application from the external heatsource tends to be different between the first temperature detector 505and the second temperature detector 506. In this instance, the firsttemperature signal Sa1 can be corrected by the second temperature signalSa2 by leveraging the fact that the difference in degree of heatapplication on the temperature detectors 505 and 506 is easily reflectedin the difference in the temperature signal Sa1 and Sa2, which is thedetection result of the temperature detectors 505 and 506. This makes itpossible to improve the measurement accuracy of the correction valuesignal Sc which is the temperature measurement value.

According to the present embodiment, both the first temperature detector505 and the second temperature detector 506 are disposed in the inwardpart 501 of the air flow meter 14. For that reason, the heat appliedfrom the external heat source to the temperature detectors 505 and 506is not excessively large as compared with the heat applied from theintake air flowing through the intake passage 12. In other words, thedifference between each of the first temperature signal Sa1 and thesecond temperature signal Sa2, and the actual temperature Sd of theintake air is not excessively large. In this instance, since the firsttemperature signal Sa1 tends to have an appropriate value as thedetected value and the second temperature signal Sa2 tends to have anappropriate value as the correction value, the measurement accuracy ofthe correction value signal Sc can be enhanced.

According to the present embodiment, both the first temperature detector505 and the second temperature detector 506 are included in the sensorSA 50. In this instance, the detection board 22 a, the lead frame 82,and the like in the sensor SA 50 can be used as a circuit board forinstalling the temperature detectors 505 and 506, and therefore, thereis no need to install a dedicated circuit board in the housing 21. Forthat reason, as compared with a configuration in which at least one ofthe temperature detectors 505 and 506 is not mounted on the sensor SA50, the design load, the cost load, and the like can be reduced.

According to the present embodiment, the air flow meter 14 includes theflow rate detector 22 in addition to the temperature detectors 505 and506. For that reason, the first temperature signal Sa1 can be correctedwith the use of a correction parameter of the flow rate, which is aphysical quantity different from that of the air. For example, the flowrate signal Sa3 can be used for correcting the first temperature signalSa1 by leveraging the phenomena that the convergence of the firsttemperature signal Sa1 to the first convergence value Ev1 is easilychanged in accordance with the flow rate signal Sa3 indicating theamount of intake air flowing through the intake passage 12. Themeasurement accuracy of the correction value signal Sc can be enhancedby the flow rate signal Sa3.

According to the present embodiment, both the first temperature detector505 and the flow rate detector 22 are provided in the measurement flowchannel 32. When the circuit board on which the first temperaturedetector 505 is mounted, and the circuit board on which the flow ratedetector 22 is mounted can be shared, so that the cost burden of thesensor SA 50 can be reduced. In addition, since both the firsttemperature signal Sa1 and the flow rate signal Sa3 are intended todetect the intake air flowing through the measurement flow channel 32,the intake air is likely to be the same as the detection target of thefirst temperature signal Sa1 and the detection target of the flow ratesignal Sa3. Therefore, in the configuration in which the firsttemperature signal Sa1 to be corrected is corrected by the flow ratesignal Sa3 as the correction parameter, the correction accuracy can beenhanced.

According to the present embodiment, since the first temperature signalSa1 is corrected using the second temperature signal Sa2 as a correctionparameter, the correction accuracy of the correction value signal Sc canbe enhanced. In addition, since the temperature differential signal Sb2is used as the correction parameter, the correction accuracy of thecorrection value signal Sc can be enhanced by using a relativelychanging mode of the second temperature signal Sa2 to the firsttemperature signal Sa1.

According to the present embodiment, correction of the temperaturedifferential signal Sb2 is performed so that as the temperaturedifferential signal Sb2 is larger, the differential correction signalSb3 is larger. For that reason, the error of the correction value signalSc with respect to the actual temperature Sd of the intake air can bereduced more than the error of the first temperature signal Sa1 withrespect to the actual temperature Sd. In other words, the measurementaccuracy of the correction value signal Sc can be enhanced.

According to the present embodiment, the flow rate signal Sa3 is used tocorrect the first temperature signal Sa1 together with the secondtemperature signal Sa2. For that reason, the second temperature signalSa2 can improve the measurement accuracy of the correction value signalSc, while the flow rate signal Sa3 can improve the response of thecorrection value signal Sc.

According to the present embodiment, the temperature is detected as thesame kind of physical quantity by the two detectors, that is, the firsttemperature detector 505 and the second temperature detector 506. Forthat reason, the first temperature signal Sa1 can be corrected with highaccuracy after the degree of heat application from the external heatsource is properly grasped by the temperature signals Sa1 and Sa2. Inother words, the measurement accuracy of the correction value signal Sccan be enhanced.

According to the present embodiment, the first temperature signal Sa1 iscorrected based on the behavior of change of the first temperaturesignal Sa1. Since a future value of the first temperature signal Sa1 canbe predicted, a time required for the first correction signal Sb1 toreach the first convergence value Ev1 can be shortened more than a timerequired for the first temperature signal Sa1 to reach the firstconvergence value Ev1. Therefore, the response of the correction valuesignal Sc can be enhanced. Moreover, both of the behavior of change ofthe first temperature signal Sa1 and the second temperature signal Sa2are used for the first temperature signal Sa1, thereby being capable ofenhancing both of the response and the measurement accuracy of thecorrection value signal Sc.

According to the present embodiment, the flow rate signal Sa3 is usedfor correcting the first temperature signal Sa1 together with thebehavior of change of the first temperature signal Sa1. For that reason,the response of the correction value signal Sc enhanced by the behaviorof change of the first temperature signal Sa1 can be further enhanced bythe flow rate signal Sa3. In addition, since the behavior of change ofthe first temperature signal Sa1 is used for the correction of thesecond temperature signal Sa2 together with the second temperaturesignal Sa2, the response of the correction value signal Sc, which isless likely to be improved by the second temperature signal Sa2, can beenhanced.

According to the present embodiment, as the flow rate signal Sa3 issmaller, the correction amount signal Sb5 is larger. For that reason,the response of the correction value signal Sc can be enhanced byleveraging the phenomena that the response of the first temperaturesignal Sa1 tends to decrease more as the flow rate of the intake airdecreases more, for example, when the flow velocity of the intake air inthe intake passage 12 is smaller.

Second Embodiment

In the first embodiment, the shape of the longitudinal partition wall 69is set irrespective of the shape of the detection throttle portion 59,but in a second embodiment, a shape of a longitudinal partition wall 69is set according to a shape of a detection throttle portion 59. In thepresent embodiment, differences from the first embodiment will be mainlydescribed.

As shown in FIGS. 58 and 59, the longitudinal partition wall 69 has awall main body 69 a and a wall bulging portion 69 b. The wall main body69 a and the wall bulging portion 69 b are aligned in the widthdirection X, and the wall bulging portion 69 b is arranged on a frontside of a sensor SA 50 in the width direction X. The wall bulgingportion 69 b extends from the detection throttle portion 59 toward ahousing tip side in the height direction Y, and has the same shape asthe shape of a portion of the detection throttle portion 59 on a frontside of the wall main body 69 a.

In the depth direction Z, a depth dimension D9 of the wall main body 69a is smaller than a depth dimension D1 of the detection throttle portion59, and a depth dimension D10 of the wall bulging portion 69 b is thesame as or larger than the depth dimension D1 of the detection throttleportion 59. Also, in the present embodiment, when it is assumed that thelongitudinal partition wall 69 and the detection throttle portion 59 areintegral parts, even if the part as a whole comes closer to a housingopening 61, the part does not become thick. For that reason, at the timeof molding the housing 21 with resin, an inward portion 93 of an innerperipheral mold portion 91 that enters an internal space 24 a can beremoved from the detection throttle portion 59 and the longitudinalpartition wall 69, and the inward portion 93 can be extracted from thehousing opening 61.

Third Embodiment

In the first embodiment, the width housing protrusion 72 a of thehousing body 24 is provided at a position facing the front surface ofthe sensor SA 50, whereas in a third embodiment, a width housingprotrusion 72 a is provided at a position facing a back surface of asensor SA 50. In the present embodiment, differences from the firstembodiment will be mainly described.

As shown in FIG. 60, the width housing protrusion 72 a abuts against aback SA protrusion 71 b, not a front SA protrusion 71 a of the sensor SA50. For that reason, the front SA protrusion 71 a of the sensor SA 50abuts against a front surface of an inner peripheral surface of ahousing body 24. In FIG. 60, a flow rate detector 22 is exposed on aleft side surface of the sensor SA 50, and the left side surface isreferred to as a front surface, and a right side surface is referred toas a back surface. On the other hand, in FIG. 14 of the firstembodiment, the flow rate detector 22 is exposed on the right sidesurface of the sensor SA 50, and the right side surface is referred toas the front surface, and the left side surface is referred to as theback surface.

In the present embodiment, as described above, since the front SAprotrusion 71 a abuts against the front surface of the inner peripheralsurface of the housing body 24, a separation distance between the frontsurface and the flow rate detector 22 is defined by a protrusiondimension of the front SA protrusion 71 a. In other words, theseparation distance between the inner peripheral surface of thedetection path 32 a and the flow rate detector 22 is defined regardlessof the width housing protrusion 72 a. For that reason, even in aconfiguration in which the back SA protrusion 71 b deforms the widthhousing protrusion 72 a with the insertion of the sensor SA 50 into theinternal space 24 a, the separation distance between the innerperipheral surface of the detection path 32 a and the flow rate detector22 is set regardless of the degree of deformation of the width housingprotrusion 72 a. In this case, since a manufacturing variation hardlyoccurs in the separation distance between the inner peripheral surfaceof the detection path 32 a and the flow rate detector 22, the detectionaccuracy by the flow rate detector 22 can be inhibited from varying fromproduct to product.

In addition, a depth housing protrusion 72 b of the present embodimentis provided at a position facing the sensor SA 50 in the downstream-sideouter peripheral portion of the housing body 24, not the upstream-sideouter peripheral portion. The depth housing protrusion 72 b extendstoward a curved surface 45 of the housing body 24 in a directioninclined with respect to the depth direction Z. In the aboveconfiguration, the sensor SA 50 is pressed against the curved surface 45in the internal space 24 a by the deformation of the depth housingprotrusion 72 b pressed by the end face of a junction portion 52 of thesensor SA 50. As a result, the positioning accuracy of the sensor SA 50with respect to the housing 21 can be enhanced in the depth direction Zas well.

Fourth Embodiment

In the first embodiment, the housing opening 61 is opened in the heightdirection Y, but in the fourth embodiment, a housing opening 61 isopened in the width direction X. In the present embodiment, an air flowmeter 200 is included in a combustion system instead of the air flowmeter 14 as the physical quantity measurement device, and differencesfrom the first embodiment will be mainly described.

As shown in FIGS. 61 and 62, the air flow meter 200 is provided in theintake passage 12. The air flow meter 200 is a physical quantitymeasurement device similar to the air flow meter 14 of the firstembodiment, and is attached to an intake pipe 12 a (refer to FIGS. 2 and8). The air flow meter 200 includes a housing 201, a flow rate detector202, and a sealing member 206, and the housing 201 includes a housingbody 204, a sealing holder 205, a flange portion 207, and a connectorportion 208. Those members and parts correspond to members and partshaving the same names as those of the first embodiment.

In the housing 201, one end face is referred to as a housing tip endface 215, the other end face is referred to as a housing base end face216, and further, in the height direction Y, the housing tip end face215 side is referred to as a housing tip side, and the housing base endface 216 side is referred to as a housing base end side. In the presentembodiment, the housing body 204, the sealing holder 205, the flangeportion 207, and the connector portion 208 are arrayed in the statedorder from the housing tip side, and the housing body 204 extends fromthe sealing holder 205 toward the housing tip side. In the air flowmeter 200, the housing body 204 and a part of the sealing holder 205 areincluded in the inward part which enters the interior of the intake pipe12 a, and the housing tip end face 215 is further included in the inwardportion. A part of the sealing holder 205, the flange portion 207, andthe connector portion 208 are included in an outward part protruding tothe outside of the intake pipe 12 a, and a housing base end face 216 isfurther included in the protrusion portion. In this case, in the housing201, the housing base end face 216 may be referred to as an end portionon the outward part side, and the housing tip end face 215 may bereferred to as an end portion on the inward part side.

The sealing member 206 is provided between the sealing holder 205 and apipe flange 12 c of an intake pipe 12 a, and is in close contact withthe sealing holder 205 and the pipe flange 12 c. Like an O-ring 26 ofthe first embodiment, the sealing member 206 is a member that restrictsan intake air from leaking out of an airflow insertion hole 12 b, and isformed in a rectangular annular shape in accordance with the shape ofthe sealing holder 205. In this case, an outer peripheral end of thesealing member 206 has a rectangular shape. In the present embodiment,while the sealing holder 205 does not have a groove portion, the flangeportion 207 extends from the sealing holder 205 toward the outerperipheral side, and the sealing member 206 is also pressed against theflange portion 207. For that reason, even if the sealing holder 205itself does not have a function of holding the sealing member 206, thesealing holder 205 and the flange portion 207 can hold the sealingmember 206. In this case, the sealing member 206 may be referred to as apressing packing.

The housing body 204 has a bypass flow channel 210. The bypass flowchannel has a passage flow channel 211, a measurement flow channel 212,an inflow port 213 a, an outflow port 213 b, and a measurement outlet213 c. The flow rate detector 202 is included in the sensor SA 220.Those members and parts correspond to members and parts having the samenames as those of the first embodiment. The sensor SA 220 includes an SAbase portion 221, a detection support portion 223, and lead terminals224 (refer to FIG. 63). The detection support portion 223 supports theflow rate detector 202, and the SA base portion 221 supports thedetection support portion 223 and the lead terminals 224. The SA baseportion 221 corresponds to the circuit accommodation portion 51 and thejunction portion 52 of the first embodiment, and the detection supportportion 223 and the lead terminals 224 are members or portionscorresponding to the sensing portion 53 and the lead terminals 54. Thesensor SA 220 may be referred to as a sensor module, a sensor assembly,or a sensor unit.

In the sensor SA 220, the flow rate detector 202, the SA base portion221, and the detection support portion 223 configure an SA main body225. In this instance, the sensor SA 220 includes an SA main body 225and the lead terminals 224. In the sensor SA 220, the SA main body 225is a portion having the flow rate detector 202, and the lead terminals224 extend from the SA main body 225.

The detection support portion 223 extends from the SA base portion 221toward the housing tip side, and the lead terminals 224 extend from theSA base portion 221 toward the housing base end side. The detectionsupport portion 223 has a size and a shape capable of placing the flowrate detector 202 in the measurement flow channel 212, and the leadterminals 224 are electrically connected to connector terminals 208 a(refer to FIG. 63) provided in the connector portion 208. Similarly tothe connector terminals 28 a of the first embodiment, the connectorterminal 208 a is electrically connected to the ECU 20 by inserting aplug portion into the connector portion 208.

The housing body 204 has an internal space 204 a in which the sensor SA220 is accommodated, and a housing opening 241 in which the internalspace 204 a is opened. The housing body 204 has wall portions 231 to 235defining the internal space 204 a, and those wall portions 231 to 235are all plate-shaped. The upstream wall portion 231 on the upstream sideof the internal space 204 a and the downstream wall portion 232 on thedownstream side of the internal space 204 a are aligned in the depthdirection Z, and are opposed to each other across the internal space 204a in a state in which the plate surfaces of the upstream wall portion231 and the downstream wall portion 232 are directed in the depthdirection Z. The front wall portion 233 opposed to the front surface ofthe sensor SA 220 and the back wall portion 234 opposed to the backsurface of the sensor SA 220 are aligned in the width direction X, andare opposed to each other across the internal space 204 a in a statewhere the respective plate surfaces of the front wall portion 233 andthe back wall portion 234 are directed in the width direction X.

A tip wall portion 235 forms a tip end face of the housing body 204, andconnects the wall portions 231 to 234 to each other. The tip wallportion 235 extends over the front wall portion 233 and the back wallportion 234 in the width direction X, and extends over the upstream wallportion 231 and the downstream wall portion 232 in the depth directionZ.

An opening direction of the housing opening 241 is different from anopening direction of the housing opening 61 of the first embodiment, andcoincides with the width direction X. The housing opening 241 is definedin the front wall portion 233. The housing opening 241 is provided at aposition closer to the sealing holder 205 in the height direction Y, andextends from the sealing holder 205 toward the housing tip side. In thatcase, the upstream wall portion 231, the downstream wall portion 232,and the back wall portion 234 extend from the sealing holder 205 towardthe housing tip side, while the back wall portion 234 is disposed at aposition spaced apart from the sealing holder 205 toward the housing tipside.

In the housing body 204, an inflow port 213 a is provided in theupstream wall portion 231, an outflow port 213 b is provided in thedownstream wall portion 232, and a measurement outlet 213 c is providedin each of the front wall portion 233 and the back wall portion 234.

The air flow meter 200 includes a potting portion 242 that closes thehousing opening 241. The potting portion 242 covers the sensor SA 220from the housing opening 241, and corresponds to a cover portion. Thepotting portion 242 is formed by curing a thermosetting resin such as apotting resin filled in the internal space 204 a, similarly to thepotting portion 65 of the first embodiment. The thermosetting resin isinjected into the internal space 204 a from the housing opening 241 in afluid state to seal the internal space 204 a. As in the firstembodiment, the thermosetting resin may be formed of an epoxy resin, aurethane resin, a silicon resin, or the like.

The sensor SA 220 is held in position so as not to be displaced in theinternal space 204 a. As shown in FIGS. 63 and 64, the housing body 204includes regulation portions 251 and 255 for regulating positionaldeviation of the sensor SA 220. Each of the regulation portions 251 and255 is formed in a plate shape, and is provided at a predeterminedinterval in the height direction Yin a state in which each plate surfaceof the regulation portions 251 and 255 is directed in the heightdirection Y. The regulation portions 251 and 255 are provided at anintermediate position of the housing body 204 in the height direction Y.

The regulation portions 251 and 255 are opposed to each other, and thesensor SA 220 is inserted between the regulation portions 251 and 255.The SA base portion 221 of the sensor SA 220 is fitted between theregulation portions 251 and 255, and the SA base portion 221 is caughtby the regulation portions 251 and 251, thereby regulating the sensor SA220 from moving in the height direction Y. The first regulation portion251 is provided on the housing tip side of the SA base portion 221, andthe second regulation portion 255 is provided on the housing base endside of the SA base portion 221. The sensor SA 220 is hardly moved inthe width direction X and the depth direction Z because the SA baseportion 221 is sandwiched between the regulation portions 251 and 255.

The internal space 204 a has a flow channel region QA defining thebypass flow channel 210 (refer to FIG. 61), a support region QBaccommodating the SA base portion 221, and a connector region QCaccommodating connection portions between the connector terminals 208 aand the lead terminals 224. In the height direction Y, the supportregion QB is disposed between the flow channel region QA and theconnector region QC. The flow channel region QA and the support regionQB are separated by the first regulation portion 251, and the supportregion QB and the connector region QC are separated by the secondregulation portion 255. An end face of the sealing holder 205 on thehousing base end side faces the second regulation portion 255 across theconnector region QC, and the connector region QC is also partitioned bythose sealing holders 205. In the height direction Y, a boundary betweenthe flow channel region QA and the support region QB is disposed at thecenter of the first regulation portion 251, and a boundary between thesupport region QB and the connector region QC is disposed at the centerof the second regulation portion 255.

The potting portion 242 is not filled in all regions of the internalspace 204 a, but is filled in the support region QB and the connectorregion QC, but is not filled in the flow channel region QA. The supportregion QB and the connector region QC are regions opened to the outsidethrough the housing opening 241, and the operator can inject thethermosetting resin from the housing opening 241 into the support regionQB and the connector region QC.

The first regulation portion 251 is provided between the front wallportion 233 and the back wall portion 234 in the width direction X, andextends over the wall portions 233 and 234. The first regulation portion251 is provided between the upstream wall portion 231 and the downstreamwall portion 232 in the depth direction Z, and extends over the wallportions 231 and 232. The first regulation portion 251 is provided witha first insertion portion 252 through which the detection supportportion 223 of the sensor SA 220 is inserted. The first insertionportion 252 is a notch that penetrates through the first regulationportion 251 in the height direction Y, and extends from the front endportion of the first regulation portion 251 toward the back wall portion234 at an intermediate position of the first regulation portion 251 inthe depth direction Z. The first insertion portion 252 may be a throughhole penetrating through the first regulation portion 251.

The sensor SA 220 and the first regulation portion 251 are in closecontact with each other so that the thermosetting resin injected intothe support region QB and the connector region QC does not leak into theflow channel region QA from between the sensor SA 220 and the firstregulation portion 251 at the time of manufacturing the air flow meter200. Specifically, an end face of the SA base portion 221 on the housingtip side and an outer peripheral surface of the first regulation portion251 abut against each other so as to overlap with each other, and aninner peripheral surface of the first insertion portion 252 and an outerperipheral surface of the detection support portion 223 abut againsteach other so as to overlap with each other. In addition, because the SAbase portion 221 and the front wall portion 233 are in contact with eachother, the thermosetting resin is prevented from leaking from a gapbetween the detection support portion 223 and the front wall portion233.

Like the first regulation portion 251, the second regulation portion 255is provided between the upstream wall portion 231 and the downstreamwall portion 232 in the depth direction Z, and extends over the wallportions 231 and 232. On the other hand, unlike the first regulationportion 251, the second regulation portion 255 extends from the backwall portion 234 toward the housing opening 241 in the width directionX, and is not connected to the front wall portion 233. The secondregulation portion 255 is provided with a second insertion portion 256through which the lead terminals 224 of the sensor SA 220 are inserted.The second insertion portion 256 is a notch that penetrates through thesecond regulation portion 255 in the height direction Y, and extendsfrom the front end portion of the second regulation portion 255 towardthe back wall portion 234 at an intermediate position of the secondregulation portion 255 in the depth direction Z.

In the second regulation portion 255, as described above, the SA baseportion 221 comes in contact with the second regulation portion 255,thereby regulating the sensor SA 220 from moving toward the housing baseend side. The SA base portion 221 is sandwiched between the front wallportion 233 and the back wall portion 234. In this instance, the frontsurface of the SA base portion 221 comes in contact with the front wallportion 233, and the back surface of the SA base portion 221 comes incontact with the back wall portion 234, thereby regulating the sensor SA220 from moving in the width direction X.

The back wall portion 234 is provided with an accommodating recessportion 264 for accommodating the back plate surface of the SA baseportion 221. The accommodating recess portion 264 is defined byrecessing the inner peripheral surface of the back wall portion 234toward the outer peripheral side, and is disposed at an intermediateposition between the upstream wall portion 231 and the downstream wallportion 232 in the depth direction Z. The SA base portion 221 is fittedin the accommodating recess portion 264, and the inner peripheralsurface of the accommodating recess portion 264 regulates the sensor SA220 from moving in the depth direction Z.

Unlike the housing 21 of the first embodiment, the housing 201 is formedby assembling multiple components together. The housing 201 includes abase member 261 and a cover member 262. The cover member 262 has atleast a front wall portion 233 of the housing body 204, and isintegrally molded as a member separate from the base member 261. Thebase member 261 includes a portion of the housing body 204 excluding thecover member 262, a sealing holder 205, a flange portion 207, and aconnector portion 208, and those portions are integrally molded.

An internal space of the base member 261 is opened toward a sideopposite to the back wall portion 234 across the upstream wall portion231, the downstream wall portion 232, and the tip wall portion 235,because the base member 261 does not have the front wall portion 233.When the open portion is referred to as a base opening 263, the baseopening 263 is closed by the cover member 262 and the potting portion242 in a state where the housing 201 is completed.

An accommodation notch portion 265 accommodating the cover member 262 isprovided in the base member 261 so that a step does not occur at theboundary between the base member 261 and the cover member 262 on thesurface of the housing body 204. The accommodation notch portion 265extends over the upstream wall portion 231, the downstream wall portion232, the tip wall portion 235, and the first regulation portion 251, andnotches the front end portion of the base member 261. Since the covermember 262 enters the accommodation notch portion 265, a portion formedby the upstream wall portion 231 and the downstream wall portion 232 anda portion formed by the cover member 262 are flush with each other onthe surface of the housing body 204.

In the present embodiment, the flow rate detector 202 corresponds to aphysical quantity detector, and the sensor SA 220 corresponds to adetection unit. In FIG. 63, FIG. 64, and the like, illustration of thebypass flow channel 210 is omitted. FIG. 63 is a partial cross-sectionalview showing a cross section of only a portion of the housing 201 closerto the housing tip side than the sealing holder 205. FIG. 64 is a viewof the housing 201 seen from the open side of the base member 261 in astate where the potting portion 242 and the cover member 262 areremoved.

Next, referring to FIGS. 65 to 68, a manufacturing method of the airflow meter 200 will be described focusing on a procedure of mounting thesensor SA 220 to the housing 201.

In the housing body 204, the base member 261 and the cover member 262are produced by performing resin molding. In the production of the basemember 261, the base member 261, which is in a state where the connectorterminals 208 a are embedded, is molded with resin by temporarilydetachably attaching the connector terminals 208 a to a mold device suchas a mold, and injecting molten resin into the mold device in thisstate, thereby molding the base member 261. When the mold device is tobe removed from the base member 261, the temporary attachment of theconnector terminals 208 a to the mold device is released, and the molddevice is removed from the base member 261. In the resin-molded basemember 261, as shown in FIG. 65, one end portions of the connectorterminals 208 a protrude from the sealing holder 205 toward the housingtip side.

Then, as shown in FIG. 66, the cover member 262 is attached to the basemember 261 so that a part of the base opening 263 is closed with thecover member 262. As a result, the housing 201, the housing body 204,and the housing opening 241 are produced. In this example, the basemember 261 and the cover member 262 are joined to each other by bondingor welding in a portion where the base member 261 and the cover member262 are in contact with each other.

Subsequently, as shown in FIG. 67, the sensor SA 220 is attached to thehousing body 204 by inserting the sensor SA 220 into the internal space204 a from the housing opening 241. In this example, the sensor SA 220is pushed in such a manner that the SA base portion 221 is fittedbetween the first regulation portion 251 and the second regulationportion 255 while the detection support portion 223 is inserted into thefirst insertion portion 252, and the SA base portion 221 is also fittedinto the accommodating recess portion 264. Thereafter, the leadterminals 224 and the connector terminals 208 a are electricallyconnected to each other by welding or the like.

As shown in FIG. 68, after the housing body 204 has been completed byassembling the cover member 262 to the base member 261, thethermosetting resin in a fluid state is injected from the housingopening 241 into the support region QB and the connector region QC. Thesupport region QB and the connector region QC are filled with thethermosetting resin so that the connector terminals 208 a, the leadterminals 224, and the sensor SA 220 are not exposed from the housingopening 241. Thereafter, the thermosetting resin is cured by heating toform the potting portion 242.

<Description of Configuration Group C>

The configuration group C relating to the positional relationshipbetween the housing attachment and the position holder will be describedwith reference to FIGS. 61 to 64, 69 to 71, and the like. In FIG. 69,the upstream wall portion 231, the downstream wall portion 232, thefront wall portion 233, and the back wall portion 234 of the base member261 of the housing body 204 are not illustrated.

In FIGS. 61 to 64, the sealing holder 205 is thicker than the housingbody 204. In the sealing holder 205, like the ring holding portion 25 ofthe first embodiment, the outer peripheral end of the lateral crosssection is circular, while the housing body 204 extending from the endface of the sealing holder 205 on the housing tip side is rectangular inlateral cross section. The sealing holder 205 is thick so as to be ableto secure a strength necessary for supporting the air flow meter 200. Inthe housing 201, the housing attachment attached to the intake pipe 12 aincludes the sealing holder 205 and the flange portion 207.

As described above, in the housing body 204, the first regulationportion 251 and the second regulation portion 255 regulate the movementof the sensor SA 220, and each of the regulation portions 251 and 255corresponds to a position holder. In the housing body 204, the upstreamwall portion 231, the downstream wall portion 232, and the back wallportion 234 connect the sealing holder 205 and the regulation portions251 and 255, and those wall portions 231, 232, and 234 correspond to ahousing connector. The internal space 204 a corresponds to anaccommodation space in which the sensor SA 220 is accommodated.

In the first regulation portion 251, the plate surface 251 a on thehousing base end side comes in contact with the SA base portion 221, andthe plate surface 251 regulates the sensor SA 220 from moving toward thehousing tip side. In the second regulation portion 255, the platesurface 255 a on the housing tip side comes in contact with the SA baseportion 221, and the plate surface 255 a regulates the sensor SA 220from moving toward the housing base end side. In this instance, theplate surfaces 251 a and 255 a are positioned and held so that thesensor SA 220 does not move in the height direction Y, and inparticular, the plate surface 251 a of the first regulation portion 251corresponds to a third holding portion.

In the SA base portion 221, the end face 221 a on the housing tip sidecomes in contact with the plate surface 251 a of the first regulationportion 251, and the end face 221 b on the housing base end side comesin contact with the plate surface 255 a of the second regulation portion255. In this case, the end faces 221 a and 221 b of the SA base portion221 correspond to a unit contact portion that is in contact with thethird holding portion.

As described above, since the outer peripheral surface of the detectionsupport portion 223 comes in contact with the inner peripheral surfaceof the first insertion portion 252, the sensor SA 220 is regulated frommoving in the width direction X and the depth direction Z. As shown inFIG. 69, the inner peripheral surface of the first insertion portion 252includes a front inner surface 252 a, a back inner surface 252 b, anupstream inner surface 252 c, and a downstream inner surface 252 d.

The front inner surface 252 a and the back inner surface 252 b arealigned in the width direction X, and the front inner surface 252 acomes in contact with the front surface of the detection support portion223, and the back inner surface 252 b comes in contact with the backsurface of the detection support portion 223. The front inner surface252 a and the back inner surface 252 b hold the sensor SA 220 inposition so as not to move in the width direction X, and correspond to afirst holding portion. The upstream inner surface 252 c and thedownstream inner surface 252 d are aligned in the depth direction Z, theupstream inner surface 252 c is disposed on the upstream wall portion231 side of the housing body 204, and the downstream inner surface 252 dis disposed on the downstream wall portion 232 side. Both of theupstream inner surface 252 c and the downstream inner surface 252 d arein contact with the side surface of the detection support portion 223,so that the sensor SA 220 is held in position so as not to move in thedepth direction Z, and correspond to a second holding portion.

In the present embodiment, as in the first embodiment, the widthdirection X corresponds to a first direction, and the depth direction Zcorresponds to a second direction. The plate surface 251 a of the firstregulation portion 251 and the inner surfaces 252 a to 252 d of thefirst insertion portion 252 may also be referred to as positioningsurfaces.

As shown in FIGS. 70 and 71, the housing body 204 has throttle portions271 and 272 for throttling the measurement flow channel 212 by reducinga flow channel area of the measurement flow channel 212. The frontthrottle portion 271 is a projection portion extending from the frontwall portion 233 toward the back wall portion 234, and the back throttleportion 272 is a projection portion extending from the back wall portion234 toward the front wall portion 233. The front throttle portion 271and the back throttle portion 272 face each other across the detectionsupport portion 223, and the flow rate detector 202 is disposed betweenthe throttle portions 271 and 272. In this case, the flow rate detector202 faces the front throttle portion 271.

In the measurement flow channel 212, a region around the flow ratedetector 202 is narrowed by the throttle portions 271 and 272, so thatthe intake air reaching the flow rate detector 202 is regulated. In thiscase, turbulence is less likely to occur in the flow of the intake airin the vicinity of the flow rate detector 202, and the detectionaccuracy of the flow rate detector 202 can be inhibited from beinglowered due to the turbulence. Like the flow rate detector 22 of thefirst embodiment, the flow rate detector 202 is a detector using theheat radiation amount of the heat generation portion, and it ispreferable that the flow rate of the intake air in the vicinity of theflow rate detector 202 is large to some extent in order to keep thedetection accuracy of the flow rate detector 202 appropriate. On theother hand, in the present embodiment, since the flow velocity of theintake air tends to increase because the measurement flow channel 212 isnarrowed by the throttle portions 271 and 272 toward the flow ratedetector 202, the detection accuracy of the flow rate detector 202 canbe optimized.

When a portion of the front wall portion 233 where the front throttleportion 271 is formed is referred to as a front forming portion 233 a,the front forming portion 233 a is thicker than other portions of thefront wall portion 233. Similarly, a portion of the back wall portion234 where the back throttle portion 272 is formed is referred to as aback forming portion 234 a, and the back forming portion 234 a isthicker than other portions of the back wall portion 234.

In this example, in the back wall portion 234, there is a concern thatthe deformation caused by the resin molding may occur in the backforming portion 234 a at the time of manufacturing the air flow meter200 since the back forming portion 234 a is thick. On the other hand, inthe base member 261 in which the back wall portion 234 and the firstregulation portion 251 are integrally molded, the back throttle portion272 is separated from the first regulation portion 251 toward thehousing tip side in the height direction Y. In this case, even if thedeformation caused by the resin molding occurs in the back formingportion 234 a, it is considered that the deformation is absorbed in aportion between the first regulation portion 251 and the back formingportion 234 a in the back wall portion 234. For that reason, theposition and shape of the first regulation portion 251 are less likelyto change with the deformation of the back forming portion 234 a, as aresult of which, the positional deviation of the flow rate detector 202is reduced.

In the housing body 204, the front forming portion 233 a is thicker thanthe back forming portion 234 a. In this case, in the width direction X,a protrusion dimension D31 of the front throttle portion 271 from thefront wall portion 233 is larger than a protrusion dimension D32 of theback throttle portion 272 from the back wall portion 234. For thatreason, even if the front forming portion 233 a is thinned as much aspossible so as not to be deformed by the resin molding, the degree ofthrottling of the measurement flow channel 212 can be appropriatelyincreased so that the detection accuracy of the flow rate detector 202can be optimized by adjusting the thickness of the front forming portion233 a. As described above, the cover member 262 having the front formingportion 233 a and the base member 261 having the first regulationportion 251 are separate members. In this case, even if the deformationattributable to the resin molding occurs in the front forming portion233 a, the position and shape of the first regulation portion 251 do notchange due to the deformation, and therefore, the positional deviationof the flow rate detector 202 does not occur due to the thicknessincrease of the front forming portion 233 a.

In the width direction X, a separation distance D33 between the frontsurface of the detection support portion 223 and the front throttleportion 271 is smaller than a separation distance D34 between the backsurface of the detection support portion 223 and the back throttleportion 272. In the measurement flow channel 212, a region between thedetection support portion 223 and the front throttle portion 271 has alarger degree of throttling than a region between the detection supportportion 223 and the back throttle portion 272. If the measurement flowchannel 212 is narrowed by the front throttle portion 271, the backthrottle portion 272 is not necessarily provided.

In the configuration group C, according to the present embodiment, inthe housing 201, the first regulation portion 251 and the secondregulation portion 255 are separated from the sealing holder 205 towardthe housing tip side. For that reason, the thickness of the sealingholder 205 can be increased to improve the strength, while the thicknessof the regulation portions 251 and 255 can be reduced. Since thethinning of the regulation portions 251 and 255 is achieved in thismanner, the shapes of the regulation portions 251 and 255 are lesslikely to vary from product to product, so that the position of thesensor SA 220 positioned by the regulation portions 251 and 255 is lesslikely to vary. Therefore, the detection accuracy of the flow ratedetector 202 can be inhibited from varying from product to product.

According to the present embodiment, in the first regulation portion251, the front inner surface 252 a and the back inner surface 252 bregulate the movement of the sensor SA 220 in the width direction X, andthe upstream inner surface 252 c and the downstream inner surface 252 dregulate the movement of the sensor SA 220 in the depth direction Z. Inthis instance, in the first regulation portion 251, since thedeformation caused by the resin molding is hardly generated in thoseinner surfaces 252 a to 252 d, the position of the sensor SA 220 in thewidth direction X and the depth direction Z can be inhibited fromvarying from product to product.

According to the present embodiment, in the first regulation portion251, the plate surface 251 a on the housing base end side regulates themovement of the sensor SA 220 toward the housing tip side. In thisinstance, in the first regulation portion 251, the plate surface 251 ais also less likely to be deformed due to resin-molding, so that theposition of the sensor SA 220 in the height direction Y can be inhibitedfrom varying from product to product.

According to the present embodiment, in the sensor SA 220, the end face221 a at the housing tip side is provided between the lead terminals 224and the flow rate detector 202 at a position closer to the flow ratedetector 202. In this instance, even if the position of the sensor SA220 is deviated so as to rotate about the contact portion with the firstregulation portion 251 as a fulcrum, the amount of positional deviationof the flow rate detector 202 can be reduced as compared with aconfiguration in which the end face 221 a is provided at a positioncloser to the lead terminals 224, for example. For that reason, thedetection accuracy of the flow rate detector 202 can be inhibited frombeing deteriorated.

According to the present embodiment, since the sealing holder 205 isconnected to the first regulation portion 251 and the second regulationportion 255 by the upstream wall portion 231, the downstream wallportion 232, and the back wall portion 234, a configuration can berealized in which the sealing holder 205 is separated from theregulation portions 251 and 255. In this case, even if the deformationcaused by the resin molding occurs in the sealing holder 205, thedeformation is absorbed by the wall portions 231, 232, and 234, so thatthe positions and shapes of the regulation portions 251 and 255 are lesslikely to change with the deformation of the sealing holder 205. Forthat reason, the positioning accuracy of the sensor SA 220 by theregulation portions 251 and 255 can be inhibited from beingdeteriorated.

According to the present embodiment, at the time of manufacturing theair flow meter 200, the sensor SA 220 is inserted into the base member261 through the base opening 263. When the sensor SA 220 is attached tothe base member 261 in this manner, the first regulation portion 251 ofthe base member 261 is less likely to be deformed by the resin molding,so that the positioning accuracy of the sensor SA 220 by the firstregulation portion 251 can be improved.

<Description of Configuration Group E>

A configuration group E relating to the position of the connectorterminals will be described with reference to FIG. 72 and the like.

As shown in FIG. 72, the connector terminals 208 a extend between theconnector portion 208 and the internal space 204 a. The connectorterminals 208 a each include a first terminal portion 282 a disposed inthe connector portion 208, a second terminal portion 282 b disposed inthe internal space 204 a, and a connection terminal portion 282 cconnecting the terminal portions 282 a and 282 b. In the connectorterminal 208 a, one end portion is included in the first terminalportion 282 a, and the other end portion is included in the secondterminal portion 282 b. The first terminal portion 282 a extends in theconnector portion 208 in a direction away from the housing body 204. Thesecond terminal portion 282 b extends away from the connector portion208 in the internal space 24 a. The second terminal portion 282 b isdisposed between the housing opening 241 and the back wall portion 234.

In the connector terminal 208 a, at least the connection terminalportion 282 c is embedded in the housing 201. The connector terminal 208a is fixed to the housing 201 by the embedded portion. The connectorterminal 208 a does not protrude into the support region QB, and theentire second terminal portion 282 b is accommodated in the connectorregion QC.

In the present embodiment, the second terminal portion 282 b correspondsto a protrusion terminal portion. In the sensor SA 220, the leadterminal 224 corresponds to a detection terminal, and the SA main body225 corresponds to a unit main body. The width direction X correspondsto a direction in which the detection unit and the housing opening arealigned.

In the sensor SA 220, the SA main body 225 is disposed at a positionextending across the flow channel region QA and the support region QB inthe height direction Y, and the lead terminals 224 are disposed at aposition extending over a boundary between the support region QB and theconnector region QC in the height direction Y. In this case, the flowchannel region QA and the support region QB configure the main bodyregion.

The lead terminals 224 and the connector terminal 208 a are connected toeach other in the connector region QC, and in the connection portion,the connector terminals 208 a do not enter between the lead terminals224 and the housing opening 241 in the width direction X. For example,in the connection portion, the lead terminals 224 are disposed betweenthe connector terminals 208 a and the housing opening 61 in the widthdirection X. The lead terminals 224 and the connector terminal 208 a maybe aligned laterally in the depth direction Z. In both cases, theconnector terminals 208 a do not enter the internal space 204 a betweenthe sensor SA 220 and the housing opening 241 in the width direction X.

Next, a manufacturing method of the air flow meter 200 will be describedwith reference to FIG. 72, center on the fact that the lead terminals224 and the connector terminals 208 a are directly connected to eachother.

After the cover member 262 has been attached to the housing 201 moldedwith resin, the sensor SA 220 is inserted into the internal space 204 athrough the housing opening 241. In this example, the sensor SA 220 ispushed into the internal space 204 a until the SA main body 225 iscaught by the back wall portion 234 or the first regulation portion 251.In this example, it is assumed that the lead terminals 224 come intocontact with the connector terminals 208 a before the SA main body 225is caught by the back wall portion 234 or the first regulation portion251. On the other hand, at least one of the lead terminals 224 and theconnector terminals 208 a are deformed, so that the sensor SA 220 can bepushed into the internal space 204 a further deeply. For that reason,even if the lead terminals 224 are disposed at the positions extendingacross the boundary between the flow channel region QA and the supportregion QB, the positional deviation of the sensor SA 220 is inhibitedfrom occurring due to the lead terminals 224 being caught by theconnector terminals 208 a.

After the sensor SA 220 has been installed in the internal space 204 a,a step of connecting the lead terminals 224 and the connector terminals208 a with the use of a joining tool is performed. In this step, as inthe first embodiment, the lead terminals 224 and the second terminalportions 282 b are directly joined to each other by sandwiching the leadterminals 224 and the second terminal portions 282 b between a pair ofwelding electrodes. Thereafter, a thermosetting resin is injected intothe internal space 204 a to form the potting portion 242.

In the configuration group E, according to the present embodiment, inthe internal space 204 a of the housing 201, the connector terminals 208a do not enter between the housing opening 241 and the sensor SA 220 inthe width direction X. For that reason, after the connector terminals208 a have been attached to the housing 201, the sensor SA 220 can beinserted into the internal space 204 a from the housing opening 241.This eliminates the need for attaching the connector terminals 208 a tothe housing 201 after the sensor SA 220 has been installed in theinternal space 204 a. For that reason, the sensor SA 220 can beinhibited from being positionally deviated due to an impact or the likecaused by the attachment of the connector terminals 208 a to the housing201.

According to the present embodiment, in the internal space 204 a, thesecond terminal portions 282 b of the connector terminals 208 a areaccommodated in the flow channel region QA and the support region QB ina state where the second terminal portions 282 b do not protrude intothe connector region QC. For that reason, a configuration can berealized in which the second terminal portions 282 b are not insertedbetween the housing opening 241 and the sensor SA 220 in the widthdirection X. When inserting the sensor SA 220 into the internal space204 a from the housing opening 241, the operator simply prevents the SAmain body 225 from entering the connector region QC, thereby beingcapable of preventing the SA main body 225 from coming in contact withthe second terminal portions 282 b. This makes it possible to inhibitthe SA main body 225 and the connector terminals 208 a from beingdamaged or deformed when the SA main body 225 and the connectorterminals 208 a are contacted with each other due to the attachment ofthe sensor SA 220 to the housing 201.

According to the present embodiment, in the internal space 204 a, thelead terminals 224 of the sensor SA 220 are disposed at positions thatextend across the boundary between the support region QB and theconnector region QC. In this case, the lead terminals 224 can beconnected directly to the connector terminals 208 a. For that reason,the number of welding operations performed in the internal space 204 afor electrically connecting the lead terminals 224 and the connectorterminals 208 a can be minimized. For that reason, the positionaldeviation of the sensor SA 220 can be inhibited from occurring due tothe weld operation in the internal space 204 a.

According to the present embodiment, the connector terminals 208 a aretemporarily attached to the mold device used for resin molding of thebase member 261, so that the base member 261 can be molded in a state inwhich at least a part of the connector terminals 208 a is embedded. Forthat reason, the positional deviation of the connector terminal 208 awith respect to the base member 261 can be inhibited from occurring.

According to the present embodiment, the sensor SA 220 and the connectorterminals 208 a are covered with the thermosetting resin injected intothe internal space 204 a from the housing opening 241. For that reason,the positional deviation of the sensor SA 220 and the deformation orbreakage of the lead terminals 224 and the connector terminals 208 a canbe inhibited by the potting portion 242 made of the thermosetting resin.

<Description of Configuration Group F>

A configuration group F relating to covering the detection unit will bedescribed with reference to FIG. 72 and the like.

As shown in FIG. 61, the housing opening 241 is disposed between thesealing holder 205 and the inflow port 213 a in the height direction Y.In this example, if the housing attachment is configured to include thesealing holder 205 and the flange portion 207, the housing opening 241is disposed between the housing attachment and the inflow port 213 a. Asdescribed above, in FIG. 72, the lead terminals 224 of the sensor SA 220and the connector terminals 208 a are connected to each other, and aconnection portion 291 is accommodated in the connector region QC. Thesupport region QB and the connector region QC configure a sealingregion, and the potting portion 242 corresponds to a filling portion. Athermosetting resin which is filled in the internal space 204 a and thencured to form the potting portion 242 corresponds to a filler.

In the configuration group F, according to the present embodiment, sincethe potting portion 242 is formed by injecting the thermosetting resininto the internal space 204 a, when the internal space 204 a is sealed,a pressure is hardly applied to the internal space 204 a. In this case,since the positional deviation of the sensor SA 220 is inhibited frombeing unintentionally caused by the pressure applied to the internalspace 204 a, the positional deviation of the sensor SA 220 hardly variesfrom product to product. Therefore, the detection accuracy of the flowrate detector 202 can be inhibited from varying from product to product.

According to the present embodiment, in the internal space 204 a, inaddition to the sensor SA 220, the connection portion 291 between thelead terminals 224 and the connector terminals 208 a is covered with thepotting portion 242. For that reason, not only the sensor SA 220 butalso the connection portion 291 can be protected by a sealingperformance of the potting portion 242.

According to the present embodiment, the housing opening 241 is disposedbetween the sealing holder 205 and the inflow port 213 a in the heightdirection Y. For that reason, a configuration can be realized in whichthe housing opening 241 is disposed in the intake passage 12 which isnot outside the intake pipe 12 a but inside the intake pipe 12 a. Inthis case, since a heat is hardly directly applied to the pottingportion 242 from a heat source such as the internal combustion engine11, the deterioration of the potting portion 242 due to heat can bereduced. As a result, the sealing performance of the internal space 204a by the potting portion 242 can be exhibited for a long period of time.

<Description of Configuration Group G>

A configuration group G relating to the information portion will bedescribed with reference to FIG. 73 and the like.

As shown in FIG. 73, in the housing 201, when an outer surface of thefront wall portion 233 is referred to as a housing front face 301 and anouter surface of the back wall portion 234 is referred to as a housingback face, the housing opening 241 is provided in the housing 201. Aplurality of thinned portions 302 recessed toward the back wall portion234 are provided on the housing front face 301. The thinned portions 302are provided on the cover member 262 forming the housing front face 301.The housing front face 301 corresponds to a housing front face which isone surface of the housing.

The housing opening 241 is an open end portion of the internal space 204a, and as described above, the internal space 204 a is sealed from thehousing opening 241 side by the potting portion 242. In the pottingportion 242, the potting surface 303, which is an outer surface thereof,faces away from the sensor SA 50 in the width direction X, as with thehousing front face 301. Further, the potting material filled in theinternal space 204 a creeps up the inner peripheral surfaces of thesupport region QB and the connector region QC, so that the peripheralportion of the potting surface 303 is easily curved. However, as a wholeof the potting surface 303, most portions except for the peripheralportion are flat surfaces. In this case, the potting portion 242corresponds to a sealing portion, and the potting surface 303corresponds to an outer surface of the sealing portion.

In the housing 201, the housing opening 241 is disposed between thesealing holder 205 and the inflow port 213 a in the height direction Y.In this case, in a state in which the air flow meter 200 is attached tothe intake pipe 12 a, both the inflow port 213 a and the potting portion242 are disposed in the intake passage 12 inside the intake pipe 12 a.

The housing opening 241 is formed in a rectangular shape as a whole. Inthis case, the housing opening 241 has a pair of first side portions305, which are long sides, and a pair of second side portions 306, whichare short sides, and has a flat shape extending in the height directionY as a whole. In this case, the first side portions 305 extend in theheight direction Y, and the second side portions 306 extend in the depthdirection Z. In the present embodiment, the four corners of the housingopening 241 are not chamfered, and the first side portions 305 and thesecond side portions 306 are directly connected to each other. The firstside portions 305 correspond to opposite sides.

The potting surface 303 is provided with an information portion 304similar to the information portion 194 in the first embodiment. In theinformation portion 304, a number string and a character string arealigned along the first side portions 305.

In the configuration group G, according to the present embodiment, sincethe potting portion 242 is formed by injecting the potting material intothe internal space 204 a, most of the potting surface 303 can beflattened. In addition, since the housing opening 241 and the internalspace 204 a are large enough to allow the sensor SA 220 to be insertedfrom the plate surface of the SA main body 225, the housing opening 241and the internal space 204 a are unlikely to cause a shortage of thepotting surface 303 in displaying the information portion 304. Asdescribed above, since the potting surface 303 is planarized andenlarged, the visibility of the information portion 304 imparted to thepotting surface 303 can be enhanced.

According to the present embodiment, in the internal space 204 a of thehousing 201, the SA main body 225 of the sensor SA 220 and the connectorterminals 208 a are aligned side by side in the height direction Y. Forthat reason, the width dimension of the internal space 204 a and thewidth dimension of the housing opening 241 are increased in the heightdirection Y to such an extent that the SA main body 225 and theconnector terminals 208 a can be disposed laterally. In other words, thewidth dimension of the potting surface 303 increases in the heightdirection Y. In this case, since the size of the information portion 304can be enlarged on the potting surface 303, the visibility of theinformation portion 304 can be enhanced.

According to the present embodiment, since the housing opening 241 isflattened as a whole so that the pair of first side portions 305 arelong sides, an alignment direction of the information portions 304 canbe clarified. In this case, since the number string and the characterstring of the information portion 304 are aligned along the first sideportions 305 on the potting surface 303, the operator can be inhibitedfrom reading the number string and the character string incorrectly. Inthis manner, the visibility of the information portion 304 can beenhanced by the shape of the potting surface 303.

According to the present embodiment, the housing front face 301 isprovided with thinned portions 302. In this example, if an attempt ismade to secure a flat surface on the housing front face 301 that islarge enough to prevent the visibility of the information portion 304from being insufficient, there is a fear that the thinned portions 302on the housing front face 301 will be insufficient. If the housing frontface 301 is short of the thinned portions 302, the cover member 262becomes thick, which may cause unintentional deformation of the covermember 262 due to curing of the molten resin when molding the covermember 262. On the other hand, in the present embodiment, since theinformation portion 304 is provided on the potting surface 303, there isno need to secure a flat surface suitable for display of the informationportion 304 on the housing front face 301. In this case, when asufficient amount of the thinned portions 302 are disposed on thehousing front face 301, the deformation of the cover member 262 due toresin molding can be reduced, and the visibility of the informationportion 304 on the potting surface 303 can be enhanced.

According to the present embodiment, in the internal space 204 a of thehousing 201, the sensor SA 220 is covered with the potting portion 242.In this example, unlike the present embodiment, for example, in aconfiguration in which a lid member molded of resin as a memberdifferent from the housing 201 is attached to the housing opening 241,as the housing opening 241 is larger, the lid member becomes larger.When the lid member is increased in size, there is a need to form thethinned portions 302 on the lid member as well as on the cover member262, which makes it difficult to secure a flat surface to the extentthat the information portion 304 can be provided by the lid member.

On the other hand, according to the present embodiment, the pottingportion 242 to which the information portion 304 is added does not needto form the thinned portions 302 because the resin molding is notperformed. Moreover, in the potting portion 242 filled in the internalspace 204 a, the phenomenon that the potting surface 303 is inevitablyflattened is leveraged, thereby being capable of disposing theinformation portion 304 almost entirely on the potting surface 303.Therefore, the visibility of the information portion 304 can be enhancedon the potting surface 303.

Fifth Embodiment

In the first embodiment, a part of the flow channel boundary portion 34and a part of the outflow port 33 b overlap with each other, but in afifth embodiment, a flow channel boundary portion 34 and an outflow port33 b are separated from each other in the depth direction Z. The presentembodiment will be described with reference to FIGS. 74 to 79 focusingon differences from the first embodiment.

<Description of Configuration Group D>

A configuration group D relating to the configuration of the passageflow channel will be described. As shown in FIGS. 74 and 75, a passageflow channel 31 has a shape extending downstream of the flow channelboundary portion 34 in the depth direction Z. In this case, in additionto an inflow passage 31 a and an outflow passage 31 b, the passage flowchannel 31 has a connection passage 331 that connects the inflow passage31 a and the outflow passage 31 b. The connection passage 331 isprovided between the inflow passage 31 a and the outflow passage 31 b,and extends from the flow channel boundary portion 34 toward a passagefloor surface 152. In this case, the outflow passage 31 b is locatedbetween the flow channel boundary portion 34 and the outflow port 33 bin the depth direction Z.

In the passage flow channel 31, the whole of the passage floor surface152 is a floor throttle surface 152 a. In this case, the floor throttlesurface 152 a is in a state of extending over the inflow port 33 a andthe outflow port 33 b. The floor throttle surface 152 a corresponds to afloor inclined surface. The wall throttle surface 153 a is providedbetween the flow channel boundary portion 34 and the outflow port 33 bin the depth direction Z, and is disposed in the entire outflow passage31 b in the depth direction Z. In this case, the wall throttle surface153 a extends over the connection passage 331 and the outflow port 33 b.

A passage ceiling surface 151 has an inflow ceiling portion 332 aprovided on the inflow port 33 a side of the flow channel boundaryportion 34, and an outflow ceiling portion 332 b provided on the outflowport 33 b side of the flow channel boundary portion 34. The inflowceiling portion 332 a extends across the inflow port 33 a and the flowchannel boundary portion 34, and extends in the depth direction Z whichis a direction in which the inflow port 33 a and the outflow port 33 bare aligned. The outflow ceiling portion 332 b extends over the flowchannel boundary portion 34 and the outflow port 33 b, and is inclinedwith respect to the inflow ceiling portion 332 a by being directedtoward the inflow port 33 a side.

The flow channel boundary portion 34 is inclined with respect to theinflow ceiling portion 332 a by being directed toward the outflow port33 b side in the same manner as that in the first embodiment. The floorthrottle surface 152 a is also inclined with respect to the inflowceiling portion 332 a. An inclination angle 83 of the floor throttlesurface 152 a with respect to the inflow ceiling portion 332 a is equalto or larger than an inclination angle 82 of the flow channel boundaryportion 34 with respect to the inflow ceiling portion 332 a. Asdescribed above, the flow channel boundary portion 34 corresponds to abranch boundary. In addition, similarly to the first embodiment, even ifa person looks into the passage flow channel 31 from the inflow port 33a in the depth direction Z, the flow channel boundary portion 34 ishidden on the back side of a ceiling surface of the inflow passage 31 aand is not visible. In this case, even if foreign matter such as dust,dust, waterdrops, and oil droplets fly along with an intake air, theforeign matter easily travels straight along the passage flow channel 31and is discharged from the outflow port 33 b. For that reason, theforeign matter does not reach the flow rate detector 22, thereby beingcapable of preventing the detection element 22 b from being damaged dueto the foreign matter, and the detection accuracy of the flow ratedetector 22 from being deteriorated due to the accumulation of theforeign matter.

Next, the mold device 90 will be described with reference to FIGS. 76and 77.

As shown in FIGS. 76 and 77, an introduction molding portion 97 b of ameasurement molding portion 97 does not reach the outflow port 33 b, anddoes not abut against outer peripheral mold portions 102 and 103. Forthat reason, unlike the first embodiment, the introduction moldingportion 97 b does not have an outer measurement surface 161 that abutsagainst the outer peripheral mold portions 102 and 103. An innermeasurement surface 162 of the measurement molding portion 97 and aninner passage surface 159 of the passage mold portion 104 abut againsteach other as in the first embodiment, and are further caught by eachother.

The measurement molding portion 97 has a mold projection portion 334 inwhich the inner measurement surface 162 protrudes toward the innerpassage surface 159, and the passage mold portion 104 has a mold recessportion 335 in which the inner passage surface 159 is recessed towardthe opposite side of the inner measurement surface 162. In both thewidth direction X and the depth direction Z, the mold projection portion334 is disposed at an intermediate position of the inner measurementsurface 162, and the mold recess portion 335 is disposed at anintermediate position of the inner passage surface 159. In that case,since the mold projection portion 334 is fitted into the mold recessportion 335, so that the four sides of the mold projection portion 334are surrounded by an inner peripheral surface of the mold recess portion335. For that reason, the mold projection portion 334 is caught on theinner peripheral surface of the mold recess portion 335 to restrict themovement of the measurement molding portion 97 and the passage moldportion 104 relative to each other in the width direction X and thedepth direction Z.

The inner measurement surface 162 of the measurement molding portion 97and the inner passage surface 159 of the passage mold portion 104 are incontact with each other at the flow channel boundary portion 34. On theother hand, the mold projection portion 334 passes the flow channelboundary portion 34 and enters the passage flow channel 31, and the moldprojection portion 334 and the mold recess portion 335 are fitted toeach other in the passage flow channel 31. In this case, the passagemold portion 104 does not have a portion that has entered themeasurement flow channel 32 side beyond the flow channel boundaryportion 34.

Next, a description will be given of a procedure for removing the molddevice 90 from the housing 21 molded with resin in the method ofmanufacturing the air flow meter 14.

As shown in FIG. 78, the measurement molding portion 97 is extractedfrom the measurement flow channel 32 of the housing 21 prior to thepassage mold portion 104. This is because the passage mold portion 104cannot be moved in the depth direction Z with respect to the measurementmolding portion 97 because the mold projection portion 334 is in a stateof entering the mold recess portion 335. As shown in FIG. 79, after themeasurement molding portion 97 has been extracted from the housing 21,the passage mold portion 104 is extracted from the inflow port 33 a ofthe housing 21.

When the passage mold portion 104 is extracted from the inflow port 33a, the passage mold portion 104 is moved to the inflow port 33 a sidealong the floor throttle surface 152 a of the passage flow channel 31.For example, when the passage mold portion 104 is moved to the inflowport 33 a side along the inflow ceiling portion 332 a of the passageflow channel 31, the inner passage surface 159 is caught by an upstreamend portion of the inflow ceiling portion 332 a and cannot be extractedfrom the inflow port 33 a. This is because at least a part of the innerpassage surface 159 of the passage mold portion 104 is disposed closerto a housing base end side than the inflow port 33 a in the heightdirection Y.

In addition, unlike the present embodiment, in the configuration inwhich the inclination angle 83 of the floor throttle surface 152 a issmaller than the inclination angle 82 of the flow channel boundaryportion 34, the passage mold portion 104 is shaped to be thickenedtoward the outer passage surface 158. For that reason, even if thepassage mold portion 104 is moved toward the inflow port 33 a side alongthe floor throttle surface 152 a of the passage flow channel 31, thepassage mold portion 104 cannot be extracted from the inflow port 33 a.In this case, in the passage mold portion 104, a separation distancebetween the floor throttle molding surface 156 and the inner passagesurface 159 gradually increases toward the outer passage surface 158.

Further, unlike the present embodiment, even if the outflow ceilingportion 332 b of the passage flow channel 31 does not face the inflowport 33 a side, but faces the outflow port 33 b side, the passage moldportion 104 becomes thicker toward the outer passage surface 158. Forthat reason, the passage mold portion 104 cannot be extracted from theinflow port 33 a.

In the configuration group D, according to the present embodiment, sincethe mold projection portion 334 enters the mold recess portion 335 inthe mold device 90, a relative positional deviation between themeasurement molding portion 97 and the passage mold portion 104 can beregulated. Moreover, since the four sides of the mold projection portion334 are surrounded by the inner peripheral surface of the mold recessportion 335, the relative positional deviation between the measurementmolding portion 97 and the passage mold portion 104 can be regulated inboth the width direction X and the depth direction Z. For that reason,the measurement molding portion 97 and the passage mold portion 104 aredisplaced from each other and a step is formed at the boundary betweenthe mold portions 97 and 104, as a result of which a step can beinhibited from occurring on the inner peripheral surfaces of the passageflow channel 31 and the measurement flow channel 32. This makes itpossible to inhibit that the air flow is disturbed by the step formed onthe inner peripheral surface of the passage flow channel 31 or themeasurement flow channel 32, and the detection accuracy of the flow ratedetector 22 is lowered.

According to the present embodiment, the inclination angle 83 of thefloor throttle surface 152 a is equal to or larger than the inclinationangle 82 of the flow channel boundary portion 34 with reference to thedepth direction Z. For that reason, in order to inhibit the entry of theforeign matter into the measurement flow channel 32, even if the flowchannel boundary portion 34 is inclined with respect to the depthdirection Z so as to face the side of the outflow port 33 b, aconfiguration can be realized in which the passage mold portion 104 canbe extracted from the inflow port 33 a.

Sixth Embodiment

In a sixth embodiment, a lead terminal 54 of a sensor SA 50 is connectedto a connector terminal 28 a through no bridge terminal 86. The presentembodiment will be described with reference to FIGS. 80 and 81 focusingon differences from the first embodiment.

<Description of Configuration Group E>

A configuration group E relating to the position of the connectorterminal will be described. As shown in FIG. 80, the lead terminal 54 ofthe sensor SA 50 does not extend straight toward a housing opening 61 inthe height direction Y, but is bent so as to extend toward the connectorterminal 28 a.

The lead terminal 54 has a first lead portion 341 extending from an SAmain body 170, a second lead portion 342 extending along a secondterminal portion 172 b of the connector terminal 28 a, and a third leadportion 343 connecting the lead portions 341 and 342. The first leadportion 341 extends from the SA main body 170 toward a housing opening61. The second lead portion 342 is disposed closer to the connectorterminal 28 a than the first lead portion 341, and extends from thethird lead portion 343 toward the housing opening 61. The first leadportion 341 and the second lead portion 342 extend in the heightdirection Y in parallel with each other. The third lead portion 343extends from the first lead portion 341 toward the connector terminal 28a in the width direction X. The first lead portion 341 corresponds to adetection lead portion. The second lead portion 342 and the third leadportion 343 configure a connection lead portion connected to the firstlead portion 341.

The lead terminal 54 extends across a boundary between a main bodyregion PC1 and a connector region PC2 in the width directions X. In thelead terminal 54, the first lead portion 341 is disposed in the mainbody region PC1, the second lead portion 342 is disposed in theconnector region PC2, and the third lead portion 343 is disposed at aposition extending across the boundary between the main body region PC1and the connector region PC2 in the width directions X. The leadterminal 54 corresponds to a detection terminal.

The second lead portion 342 enters between a sealing step surface 67 anda housing opening 61 in the height direction Y, and at least one of thesecond lead portion 342 and the third lead portion 343 comes in contactwith the sealing step surface 67. In this case, the sealing step surface67 supports a connection portion between the second lead portion 342 andthe second terminal portion 172 b.

Next, a method of manufacturing an air flow meter 14 will be describedwith reference to FIGS. 80 and 81, focusing on the fact that the leadterminals 54 and the connector terminal 28 a are directly connected toeach other.

First, a procedure of manufacturing the sensor SA 50 will be described.In this example, the sensor SA having high versatility is referred to asa general purpose SA, and the general purpose SA has the SA main body170 and the first lead portion 341, but does not have the second leadportion 342 and the third lead portion 343. In the present embodiment,the sensor SA 50 is manufactured by connecting the second lead portion342 and the third lead portion 343 to the first lead portion 341 of thegeneral purpose SA by welding or the like.

The sensor SA 50 is not manufactured by attaching the lead portions 342and 343 to the general purpose SA, but may be manufactured by attachingthe lead terminal 54 having the first lead portion 341, the second leadportion 342, and the third lead portion 343 to the SA main body 170. Thefirst lead portion 341 of the general purpose SA is a portioncorresponding to the lead terminals 54 of the sensor SA 50 of the firstembodiment, and the sensor SA 50 of the first embodiment can also bereferred to as a general purpose SA having high versatility.

After a housing 21 has been molded with resin, as shown in FIG. 81, thesensor SA 50 is inserted into an internal space 24 a of the housing 21.In this example, similarly to the first embodiment, the sensor SA 50inserted from the housing opening 61 is pushed into the internal space24 a until a circuit step surface 55 is caught by a region step surface66. In this example, it is assumed that the second lead portion 342 andthe third lead portion 343 of the lead terminal 54 are caught by thesealing step surface 67 before the SA main body 170 is caught by theregion step surface 66. Even in this instance, the lead terminal 54caught by the sealing step surface 67 is deformed as a whole, so thatthe sensor SA 50 can be pushed into the internal space 24 a furtherdeeply. For that reason, even if the lead terminal 54 is disposed at aposition extending across a boundary between the main body region PC1and the connector region PC2, the positional deviation of the sensor SA50 is inhibited from occurring by the lead terminal 54 being caught bythe sealing step surface 67.

After the sensor SA 50 has been installed in the internal space 24 a, astep of connecting the lead terminal 54 and the connector terminal 28 awith the use of a joining tool is performed. In this step, a pair ofwelding electrodes are inserted into the internal space 24 a from thehousing opening 61, the second bridge portion 173 b and the secondterminal portion 172 b are sandwiched by those welding electrodes, andwelding between the second bridge portion 173 b and the second terminalportion 172 b is performed. As described above, in the presentembodiment, the lead terminal 54 and the connector terminal 28 a arejoined directly to each other, so that the number of joining portionsrequiring a joining operation after the sensor SA 50 has been installedin the internal space 24 a is reduced as much as possible.

For example, in the configuration of indirectly connecting the leadterminal 54 and the connector terminal 28 a as in the first embodiment,the welding operation for the lead terminal 54 and the welding operationfor the connector terminal 28 a are performed separately. Compared tothe above configuration, in the present embodiment, since the leadterminal 54 and the connector terminal 28 a are directly joined to eachother, the number of joining portions requiring a joining operationafter the sensor SA 50 has been installed in the internal space 24 a isreduced to half.

In the configuration group E, according to the present embodiment, evenif the lead terminal 54 does not extend straight toward the housingopening 61, if the lead terminal 54 extends generally toward the housingopening 61, the second lead portion 342 is disposed in the connectorregion PC2. In other words, the second lead portion 342 is disposed at aposition closer to the housing opening 61 than the SA main body 170. Inthis case, since there is no need to insert a joining tool for joiningthe second lead portion 342 and the second terminal portion 172 b deeplyinto the internal space 24 a, a work load when joining can be reduced.

According to the present embodiment, in the internal space 24 a of thehousing 21, the lead terminal 54 of the sensor SA 50 is disposed at aposition that extends across the boundary between the main body regionPC1 and the connector region PC2. In this case, since the lead terminal54 can be directly connected to the connector terminal 28 a, the numberof welding operations performed in the internal space 24 a forelectrically connecting the lead terminal 54 and the connector terminal28 a can be minimized. For that reason, the positional deviation of thesensor SA 50 can be inhibited from occurring due to the weldingoperation in the internal space 24 a.

According to the present embodiment, since the second terminal portion172 b of the connector terminals 28 a is supported by the sealing stepsurface 67, unintentional displacement of the second terminal portion172 b can be inhibited when the second terminal portion 172 b and thesecond lead portion 342 are joined to each other. This makes it possibleto inhibit that the second terminal portion 172 b is relativelydisplaced with respect to the second lead portion 342 during the joiningoperation, which makes it difficult to properly join the second terminalportion 172 b and the second lead portion 342.

According to the present embodiment, in the lead terminal 54, the secondlead portion 342 inserted between the sealing step surface 67 and thehousing opening 61 is supported by the sealing step surface 67 from theside opposite to the housing opening 61. In this example, in the sensorSA 50, the second lead portion 342 is easily displaced because the firstlead portion 341 cantilevers the second lead portion 342 and the thirdlead portion 343. In this case, when the second lead portion 342 isjoined to the second terminal portion 172 b, the second lead portion 342is relatively displaced with respect to the second terminal portion 172b, which may increase the difficulty of the joining operation or mayprevent proper joining. On the contrary, according to the presentembodiment, since the second lead portion 342 is supported by thesealing step surface 67, a state in which the first lead portion 341cantilevers the second lead portion 342 and the third lead portion 343is eliminated. For that reason, the joining operation between the secondlead portion 342 and the second terminal portion 172 b can befacilitated.

According to the present embodiment, the sealing step surface 67supporting the second lead portion 342 of the sensor SA 50 is disposedat a position closer to the housing opening 61 than the region stepsurface 66. In this case, when the second lead portion 342 and thesecond terminal portion 172 b are joined to each other, there is no needto insert the joining tool to a position deeper than the sealing stepsurface 67 in the internal space 24 a, so that the joining tool can beinhibited from unintentionally coming into contact with the SA main body170.

According to the present embodiment, the second terminal portion 172 band the second lead portion 342 extend from the sealing step surface 67toward the housing opening 61. In this case, when the second terminalportion 172 b and the second lead portion 342 are sandwiched between ajoining tool such as welding electrodes, there is no need to insert thejoining tool into a back side of the second terminal portion 172 b andthe second lead portion 342 when viewed from the housing opening 61. Forthat reason, when the second terminal portion 172 b and the second leadportion 342 are joined to each other with the use of the joining tool,the joining operation can be facilitated.

According to the present embodiment, in the sensor SA 50, the leadterminal 54 is formed by connecting the second lead portion 342 and thethird lead portion 343 to the first lead portion 341 extending from theSA main body 170. In this instance, the sensor SA 50 can be manufacturedwith the use of a general purpose SA that does not have the second leadportion 342 and the third lead portion 343. For that reason, after theconnector terminal 28 a has been fixed to the housing 21, the sensor SA50 can be installed in the internal space 24 a of the housing 21, andthe costs for manufacturing the sensor SA 50 can be reduced.

Other Embodiments

Although a plurality of embodiments according to the present disclosurehave been described above, the present disclosure is not construed asbeing limited to the above-mentioned embodiments, and can be applied tovarious embodiments and combinations within a scope not departing fromthe spirit of the present disclosure.

<Modification of Configuration Group A>

In Modification 1, the housing 21 does not need to have the passage flowchannel 31. In other words, the bypass flow channel 30 may have only themeasurement flow channel 32. For example, the longitudinal partitionwall 69 extends to the housing bottom portion 62. In the aboveconfiguration, all of the intake air flowing in from the inflow port 33a is guided to the introduction path 32 b of the measurement flowchannel 32 and discharged from the measurement outlet 33 c. In the aboveconfiguration, in order to prevent the outflow port 33 b from beingmolded during resin molding of the housing 21, the tip portion of thepassage mold portion 104 does not abut against the outer peripheral moldportions 102 and 103 in the mold device 90.

As Modification 2, in the measurement flow channel 32, the flow ratedetector 22 may be provided in the introduction path 32 b and thedischarge path 32 c. In this case, the detection path 32 a serves as aconnection path connecting the introduction path 32 b and the dischargepath 32 c. For example, as a configuration in which the flow ratedetector 22 is provided in the introduction path 32 b, there is aconfiguration in which the sensing support portion 57 extends toward thehousing tip side to the extent that the sensing support portion 57reaches the introduction path 32 b in the sensor SA 50. In thisconfiguration, since the flow rate detector 22 is provided at a positionclose to the tip portion of the sensing support portion 57, the flowrate detector 22 can be disposed in the introduction path 32 b.

As Modification 3, in the measurement flow channel 32, the introductionpath 32 b and the discharge path 32 c may be aligned not in the depthdirection Z but in the width direction X. In this configuration, thedetection path 32 a extends in the width direction X, but the flow ratedetection by the flow rate detector 22 can be appropriately performedonly with the flow direction of the intake air in the detection path 32a being not the depth direction Z.

In Modification 4, the boundary between the sealing region PA and theopen region PB may coincide with the sensing step surface 56 instead ofthe circuit step surface 55 of the sensor SA 50. For example, the regionstep surface 66 of the housing 21 disposed at a position of abuttingagainst the sensing step surface 56 of the sensor SA 50, and the sealingregion PA and the accommodation region PB1 are sealed by the pottingportion 65. In the above configuration, a gap is not defined between theouter peripheral surface of the junction portion 52 of the sensor SA 50and the inner peripheral surface of the housing body 24 on theaccommodation region PB1.

As Modification 5, the detection throttle portions 59 may be provided onboth sides of the sensing support portion 57 in the width direction X.In this case, the housing 21 has a pair of detection throttle portions59 aligned in the width direction X, and the sensing support portion 57and the flow rate detector 22 are disposed between the detectionthrottle portions 59. Even in the above configuration, it is preferablethat the pair of detection throttle portions 59 and the longitudinalpartition wall 69 do not become thick even toward the housing opening 61as a whole. As a result, the inner peripheral surface of the housing 21can be integrally molded.

As Modification 6, in the mold device 90, the first outer peripheralmold portion 102 and the second outer peripheral mold portion 103 may bealigned in the depth direction Z instead of the width direction X. Thenumber of mold portions for molding the outer peripheral surface of thehousing 21 may be three or more instead of two as in the case of theouter peripheral mold portions 102 and 103. Further, if the housing 21can be removed from the outer peripheral surface, one mold portion formolding the outer peripheral surface of the housing 21 may be used.

As Modification 7, when the housing 21 is molded with resin, a pluralityof mold portions may be taken out from the housing opening 61, as wellas one mold portion like the inner peripheral mold portion 91. Forexample, the first inner peripheral mold portion having the introductionmolding portion 97 b and the second inner peripheral mold portion havingthe discharge molding portion 97 c are formed independently of eachother, and in the mold device 90, those inner peripheral mold portionsare combined with each other and inserted into the outer peripheral moldportions 102 and 103. Also, in the above configuration, it is preferablethat the first inner peripheral mold portion and the second innerperipheral mold portion can be pulled out from the housing opening 61collectively or sequentially.

As Modification 8, the outlet extension portion 113 for molding themeasurement outlet 33 c may be included in a dedicated mold portionindependent of the outer peripheral mold portions 102 and 103, insteadof being included in the outer peripheral mold portions 102 and 103. Forexample, a dedicated mold portion including the outlet extension portion113 is provided between the first outer peripheral mold portion 102 andthe second outer peripheral mold portion 103 in the mold device 90 inthe same manner as the passage mold portion 104. With the use of thededicated mold portion in this manner, the opening direction of themeasurement outlet 33 c can be easily changed not to the width directionX but to the depth direction Z.

In Modification 9, the measurement outlet 33 c may be provided not inthe discharge path 32 c but in the detection path 32 a. For example, themeasurement outlet 33 c is provided on the downstream side of the flowrate detector 22 in the detection path 32 a. In the above configuration,the intake air that has passed through the flow rate detector 22 isdischarged to the outside from the measurement outlet 33 c withoutpassing through the discharge path 32 c. In this case, the dischargepath 32 c may not be provided. Even in a configuration in which thedischarge path 32 c is not provided, if the introduction path 32 b isnot narrowed even when the introduction path 32 b approaches the housingopening 61 in the height direction Y, the inward portion 93 of the innerperipheral mold portion 91 can be extracted from the housing opening 61at the time of resin molding of the housing 21. In the aboveconfiguration, the inward portion 93 does not have the discharge moldingportion 97 c.

As Modification 10, the configuration functioning as the control deviceof the combustion system is not the ECU 20, but may be a variety ofcalculation devices mounted in a vehicle, and multiple calculationdevices may function as the control device in cooperation with eachother. In addition, various programs may be stored in a non-transitorytangible storage medium such as a flash memory or a hard disk providedin each calculation device.

<Modifications of Configuration Group B>

As Modification B1, in the first embodiment, the measurement outlet 33 cmay be provided on one of the front surface and the back surface of thehousing 21, instead of the measurement outlet 33 c provided on each ofthe front surface and the back surface. For example, as shown in FIGS.82 and 83, the measurement outlet 33 c is provided on the surface of thehousing 21. In the above configuration, the housing 21 has an asymmetricshape on the front side and the back side, and the outflow port 33 b isalso provided on the surface of the housing 21, not on the outerperipheral downstream end 132 b but on the surface of the housing 21 aswith the measurement outlet 33 c. The outflow port 33 b and themeasurement outlet 33 c are not formed in a rectangular shape but formedin a circular shape.

In addition to the flat surface 44 and the curved surface 45, thesurface of the housing 21 has a downstream tapered surface 401 thatextends straight in a state inclined with respect to the depth directionZ from the outer peripheral downstream end 132 b toward the upstreamside. On the surface of the housing 21, since the flat surface 44 andthe curved surface 45 are aligned horizontally in the depth direction Z,a vertical boundary 131 a linearly extends from the flange portion 27 tothe tip of the housing 21 in the height direction Y, and the verticalboundary 131 a is not formed. In addition, the flat surface 44 and thedownstream tapered surface 401 are aligned horizontally in the depthdirection Z, and a tapered boundary 402, which is a boundary between theflat surface 44 and the downstream tapered surface 401, extends inparallel with the vertical boundary 131 a. A back surface of the housing21 does not have the downstream tapered surface 401, and the flatsurface 44 extends in the depth direction Z from the outer peripheraldownstream end 132 b toward the curved surface 45.

On the surface of the housing 21, similarly to the first embodiment, themeasurement outlet 33 c is disposed at a position extending across thevertical boundary 131 a in the depth direction Z. The outflow port 33 bis provided on the flat surface 44 between the vertical boundary 131 aand the tapered boundary 402, instead of the outer peripheral downstreamend 132 b. The outflow port 33 b may be provided on the curved surface45 or the downstream tapered surface 401, or may be provided at aposition extending across the vertical boundary 131 a in the depthdirection Z similarly to the measurement outlet 33 c.

As Modification B2, in the first embodiment, the curved surface 45 ofthe housing 21 may be an outer peripheral inclined surface inclined withrespect to the depth direction Z. For example, as shown in FIG. 85, theouter peripheral inclined surface may be a tapered surface extendingstraight from the flat surface 44 toward the outer peripheral upstreamend 132 a. The outer peripheral inclined surface may be a surface curvedso as to be recessed toward the inner peripheral side of the housing 21.In either case, since the measurement outlet 33 c is disposed at aposition extending across the vertical boundary 131 a as the outerperipheral boundary, a configuration can be realized in which themeasurement outlet 33 c is not opened toward the downstream side.

As Modification B3, the measurement outlet may be provided only on theouter peripheral inclined surface out of the outer peripheral flatsurface and the outer peripheral inclined surface. For example, in thefirst embodiment, as shown in FIG. 84, the measurement outlet 33 c isprovided on the curved surface 45 so as not to protrude from the flatsurface 44. In the above configuration, the measurement outlet 33 c doesnot extends across the vertical boundary 131 a in the depth direction Z,but extends from the vertical boundary 131 a toward the outer peripheralupstream end 132 a in the depth direction Z, and the outlet downstreamend 134 b of the measurement outlet 33 c is included in the verticalboundary 131 a.

Further, as shown in FIG. 85, the measurement outlet 33 c is provided onan upstream tapered surface 404 as the outer peripheral inclined surfaceso as not to protrude to the flat surface 44. In the aboveconfiguration, an upstream tapered surface 404 is included in the outerperipheral surface of the housing 21 instead of the curved surface 45,and the boundary between the upstream tapered surface 404 and the flatsurface 44 is the vertical boundary 131 a. The upstream tapered surface404 extends straight from the vertical boundary 131 a toward the outerperipheral upstream end 132 a, and is inclined with respect to the depthdirection Z. Also, in the above configuration, the outlet downstream end134 b of the measurement outlet 33 c is included in the verticalboundary 131 a.

In either of the configurations of FIGS. 84 and 85, the measurementoutlet 33 c is disposed on the outer peripheral inclined surface and isnot opened to the downstream side. For that reason, even if theturbulence of the air flow occurs around the outer peripheral downstreamend 132 b in the intake passage 12, the flat surface 44 can inhibit theturbulence from reaching the measurement outlet 33 c. Further, as in thefirst embodiment, a forward flow air such as the air AF1 flows along theouter peripheral inclined surface before reaching the measurement outlet33 c, so that a traveling direction changes to a direction substantiallyperpendicular to the opening direction of the measurement outlet 33 c,and therefore, the forward flow air hardly flows into the measurementoutlet 33 c.

Further, as a configuration in which the measurement outlet 33 c isprovided on the curved surface 45, there is a configuration in which themeasurement outlet 33 c is disposed at an intermediate position of theouter peripheral inclined surface in the depth direction Z. For example,as shown in FIG. 86, the measurement outlet 33 c is disposed between theouter peripheral upstream end 132 a and the vertical boundary 131 a. Inthe above configuration, the upstream end portion of the upstreamtapered surface 404 is included in the outer peripheral upstream end 132a, the downstream end portion of the upstream tapered surface 404 isincluded in the vertical boundary 131 a, and the measurement outlet 33 cis disposed at a position closer to the vertical boundary 131 a in thedepth direction Z. Also, in the above configuration, similarly toModification B11, the forward flow air flows along the upstream taperedsurface 404 as the outer peripheral inclined surface before reaching themeasurement outlet 33 c, so that the forward flow air does not easilyflow into the measurement outlet 33 c.

From the viewpoint that the forward flow air hardly flows into themeasurement outlet 33 c, it is preferable that the measurement outlet 33c is placed as far as possible from the upstream end portion of theupstream tapered surface 404 or the outer peripheral upstream end 132 a.For that reason, in the depth direction Z, it is preferable that aseparation distance L18 between the vertical boundary 131 a and themeasurement outlet 33 c is smaller than a length dimension L13 of themeasurement outlet 33 c.

The measurement outlet 33 c may be disposed at a position closer to theouter peripheral upstream end 132 a in the depth direction Z. Even, inthis case, the measurement outlet 33 c and the outer peripheral upstreamend 132 a are separated from each other in the depth direction Z,thereby being capable of making it difficult for the forward flow air toflow into the measurement outlet 33 c.

As Modification B4, the measurement outlet may be provided only on theouter peripheral flat surface out of the outer peripheral flat surfaceand the outer peripheral inclined surface. For example, in the firstembodiment, the measurement outlet 33 c is provided on the flat surface44 so as not to protrude from the curved surface 45. In the aboveconfiguration, the measurement outlet 33 c does not extend across thevertical boundary 131 a in the depth direction Z, but extends from thevertical boundary 131 a toward the outer peripheral downstream end 132 bin the depth direction Z, and the outlet upstream end 134 a of themeasurement outlet 33 c is included in the vertical boundary 131 a.Also, in the above configuration, if the outlet downstream end 134 b ofthe measurement outlet 33 c and the downstream end portion of the flatsurface 44 are separated from each other in the depth direction Z, evenif the turbulence of the air flow occurs in the periphery of thedownstream end portion of the flat surface 44 or the periphery of theouter peripheral downstream end 132 b, the turbulence can be inhibitedfrom reaching the measurement outlet 33 c.

Further, as shown in FIG. 120, the measurement outlet 33 c is providedon the flat surface 44 so as not to protrude from the upstream taperedsurface 404 as the outer peripheral inclined surface. In the aboveconfiguration, as in FIG. 85, the upstream tapered surface 404 isincluded in the outer peripheral surface of the housing 21 instead ofthe curved surface 45, and the boundary between the upstream taperedsurface 404 and the flat surface 44 is the vertical boundary 131 a.Also, in the above configuration, the outlet upstream end 134 a of themeasurement outlet 33 c is included in the vertical boundary 131 a.

Further, as a configuration in which the measurement outlet 33 c isprovided on the flat surface 44, there is a configuration in which themeasurement outlet 33 c is disposed at an intermediate position of theflat surface 44 in the depth direction Z. For example, as shown in FIG.87, the measurement outlet 33 c is disposed between the verticalboundary 131 a and the outer peripheral downstream end 132 b. In theabove configuration, the upstream end portion of the flat surface 44 isincluded in the vertical boundary 131 a, the downstream end portion ofthe flat surface 44 is included in the outer peripheral downstream end132 b, and the measurement outlet 33 c is disposed at a position closeto the vertical boundary 131 a in the depth direction Z. Also, in theabove configuration, similarly to Modification B13 described above, evenif the turbulence of the air flow occurs in the periphery of thedownstream end portion of the flat surface 44 or the periphery of theouter peripheral downstream end 132 b, the turbulence can be inhibitedfrom reaching the measurement outlet 33 c.

From the viewpoint of inhibiting the turbulence of the air flowgenerated in the downstream side of the measurement outlet 33 c fromreaching the measurement outlet 33 c, it is preferable that themeasurement outlet 33 c is placed as far as possible from the downstreamend portion of the flat surface 44 or the outer peripheral downstreamend 132 b. For that reason, in the depth direction Z, it is preferablethat a separation distance L19 between the vertical boundary 131 a andthe measurement outlet 33 c is smaller than a length dimension L13 ofthe measurement outlet 33 c.

As Modification B5, in the first embodiment, the discharge path 32 c ofthe measurement flow channel 32 may be narrowed toward the housing baseend side in the height direction Y. For example, as shown in FIG. 88, abulging region 406 in which a part of the discharge path 32 c is bulgedin the depth direction Z is included in the measurement flow channel 32.The bulging region 406 bulges toward the introduction path 32 b side soas to keep a state in which the discharge path 32 c and the introductionpath 32 b are separated from each other by the longitudinal partitionwall 69, and is disposed at the end portion of the discharge path 32 con the housing tip side. The measurement outlet 33 c has a portion 407 athat opens the entirety of the bulging region 406 in the width directionX, and a portion 407 b that protrudes from the longitudinal partitionwall 69 toward the opposite side of the introduction path 32 b. In thiscase, unlike the present modification, an open area of the measurementoutlet 33 c becomes large as compared with the configuration in whichthe measurement flow channel 32 does not have the bulging region 406, sothat the discharge amount of the intake air from the measurement outlet33 c can be increased. As a result, a flow velocity of the air in themeasurement flow channel 32 increases, so that the measurement accuracyof the flow rate detector 22 can be improved.

As Modification B6, in each of the embodiments described above such asthe first embodiment, the flat surface 44 and the curved surface 45 maybe included in the end face on the housing tip side or the end face onthe housing base end side in the outer peripheral surface of the housing21. In this case, the measurement outlet 33 c is provided on the endface on the housing tip side and the end face on the housing base endside in the housing 21.

As Modification B7, in each of the embodiments described above, thepositional relationship between the flat surface 44 and the curvedsurface 45 is not limited to the embodiments described above as long asthe measurement outlet 33 c is located at a position extending acrossthe flat surface 44 and the curved surface 45. For example, in the firstembodiment, the flat surface 44 may have at least one of the downstreamflat portion 137 a, the tip-side flat portion 137 b, and the baseend-side flat portion 137 c. The curved surface 45 may have at least oneof the upstream curved portion 138 a, the tip-side curved portion 138 b,and the base end-side curved portion 138 c. In short, the flat surface44 and the curved surface 45 may be disposed so that the verticalboundary 131 a extends in the height direction Y. The vertical boundary131 a may be inclined with respect to the height direction Y.

As Modification B8, in each of the embodiments described above such asthe first embodiment, the measurement outlet 33 c may be disposed at aposition of extending across the outer peripheral upstream end 132 a inthe width direction X on the outer peripheral surface of the housing 21.Even in this case, since the open area of the measurement outlet 33 c issmaller than the open area of the inflow port 33 a, a configuration canbe realized in which the forward flow air hardly flows into themeasurement outlet 33 c.

As Modification B9, in the first embodiment, as shown in FIGS. 6 and 7,and the like, the thinned portions 41 may be provided on the flatsurface 44. Even in this case, if the measurement outlet 33 c and thethinned portions 41 are separated from each other in the depth directionZ, even if the turbulence of the air flow occurs around the thinnedportions 41, the turbulence can be inhibited from reaching themeasurement outlet 33 c.

As Modification B10, in the first embodiment, the downstream definingsurface 135 b may be a curved surface instead of a tapered surface. Inshort, the downstream defining surface 135 b may be an inclined surfaceinclined with respect to the flat surface 44. Further, in theconfiguration in which the downstream defining surface 135 b is a curvedsurface, the curved surface may be curved so as to project toward theouter peripheral side of the housing 21, or may be curved so as to berecessed toward the inner peripheral side of the housing 21.

<Modifications of Configuration Group C>

As Modification C1, in the first embodiment, the accommodation wallportion 121 may not be a position holder. For example, as shown in FIG.89, the housing body 24 has a positioning portion 411, and thepositioning portion 411 protrudes from the accommodation wall portion121 toward the inner peripheral side. In the above configuration, thehousing body 24 does not have the overhanging portion 66 a, and theaccommodation wall portion 121 extends from the sealing wall portion 122toward the housing tip side. For that reason, in the height direction Y,the boundary between the accommodation wall portion 121 and the sealingwall portion 122 coincides with the boundary between the sealing regionPA and the accommodation region PB1.

The positioning portion 411 extends along the inner peripheral surfaceof the accommodation wall portion 121, and is disposed at the endportion of the accommodation wall portion 121 on the housing base endside. The positioning portion 411 is formed in a plate shape, and theplate surface 411 a on the housing base end side in the positioningportion 411 comes in contact with the circuit step surface 55 of thesensor SA 50, similarly to the region step surface 66 of the firstembodiment. The plate surface 411 a restricts the sensor SA 50 frommoving toward the housing tip side, and corresponds to a third holdingportion. The tip end face 411 b of the positioning portion 411 comes incontact with the outer peripheral surface of the junction portion 52 ofthe sensor SA 50, similarly to the tip end faces of the housingprotrusions 72 a and 72 b of the first embodiment, thereby restrictingthe sensor SA 50 from moving in the width direction X and the depthdirection Z. A portion of the tip end face 411 b which faces in thewidth direction X corresponds to a first holding portion, and a portionwhich faces in the depth direction Z corresponds to a second holdingportion.

The positioning portion 411 is provided at a position separated from thering holding portion 25 toward the housing tip side. In this case, evenif deformation due to resin molding occurs in the ring holding portion25 and the sealing wall portion 122, it is considered that thedeformation is absorbed in a portion between the ring holding portion 25and the positioning portion 411 in the housing body 24. For that reason,the position and shape of the positioning portion 411 hardly changeswith the deformation of the ring holding portion 25 and the sealing wallportion 122, as a result of which, the positional deviation of the flowrate detector 22 is inhibited.

As Modification C2, in the modification C1, the positioning portion 411may be formed of a member different from the housing body 24. Forexample, as shown in FIGS. 90 and 91, the positioning member 412 formingthe positioning portion 411 is attached to the housing body 24. Unlikethe housing body 24, the positioning member 412 is formed of aconductive metal material or the like. Since the positioning member 412has conductivity in this manner, static electricity charged in thehousing body 24 having insulating properties is easily discharged by thepositioning member 412. For that reason, the detection accuracy of theflow rate detector 22 can be inhibited from being lowered by staticelectricity.

The positioning member 412 has a depth portion 412 a extending in thedepth direction Z and a pair of width portions 412 b extending in thewidth direction X, and each width portion 412 b extends in the samedirection from both ends of the depth portion 412 a. In the positioningmember 412, the plate surface 411 a that comes in contact with thecircuit step surface 55 of the sensor SA 50 is formed by the respectiveplate surfaces of the depth portion 412 a and the width portions 412 b.A tip end face 411 b that comes in contact with the outer peripheralsurface of the junction portion 52 of the sensor SA 50 is formed by theinner peripheral surface of the positioning member 412.

A support recess portion 413 for supporting the positioning member 412is provided on the inner peripheral surface of the housing body 24. Thesupport recess portion 413 is a recess portion recessed toward the outerperipheral side, and extends in a groove shape along the end portion ofthe housing base end side of the accommodation wall portion 121. Thepositioning member 412 is fitted into the support recess portion 413with its outer peripheral end entering the support recess portion 413,and the positioning member 412 and the housing body 24 are bonded toeach other by an adhesive or the like. The depth portion 412 a of thepositioning member 412 is disposed on the front surface side of thesensor SA 50, and is not disposed on the back surface side.

The housing 21 is not integrally molded as in the first embodiment, butis formed by assembling multiple members as in the fourth embodiment.For example, after the multiple members are each molded with resin andthe positioning member 412 is molded with metal, the multiple membersare assembled to each other so that the positioning member 412 isaccommodated in the internal space 24 a.

According to the present modification, since the positioning member 412is a member separate from the housing body 24, the degree of freedom ofselection of the material forming the positioning portion 411 can beincreased. In addition, even when the shape and size are changed inaccordance with a change in the specifications of the sensor SA 50, theexisting housing 21 can be used by changing the shape and size of thepositioning member 412.

As Modification C3, the sensor SAs 50 and 220 as detection units mayinclude multiple physical quantity detectors. For example, in the fourthembodiment, the sensor SA 220 has two physical quantity detectors fordetecting physical quantities that differ from each other. As shown inFIG. 92, the sensor SA 220 with the above configuration has a firstdetector 421 for detecting the flow rate of an air and a second detector422 for detecting the temperature of the air as physical quantitydetectors. As with the flow rate detector 202 according to the fourthembodiment, the first detector 421 is provided in the measurement flowchannel 32 to detect the flow rate of the intake air in the measurementflow channel 32. As with the intake air temperature sensor 23 accordingto the first embodiment, the second detector 422 is provided outside thehousing 201, to thereby detect the temperature of the intake air in theintake passage 12.

The sensor SA 220 includes a first support portion 423 that supports thefirst detector 421 and a second support portion 424 that supports thesecond detector 422. The first support portion 423 extends from the SAbase portion 221 toward the housing tip side similarly to the detectionsupport portion 223 in the fourth embodiment. The second support portion424 extends from the SA base portion 221 toward the upstream wallportion 231 in the depth direction Z, and is disposed at a positioncloser to the end of the SA base portion 221 on the housing tip side. Anouter peripheral insertion portion 426 into which the second supportportion 424 is inserted is provided at the outer peripheral portion ofthe housing body 204, and the second detector 422 is disposed at aportion of the second support portion 424 exposed to the outside of thehousing through the outer peripheral insertion portion 426.

The housing body 204 is provided with a housing recess portion 427 whoseouter peripheral surface is formed to be recessed toward the downstreamside. The housing recess portion 427 is disposed at an intermediateposition of the housing body 204 in the height direction Y. In theupstream wall portion 231, the portion connecting the first regulationportion 251 and the second regulation portion 255 in the fourthembodiment is not provided. Instead of that portion, a regulatingconnection portion 428 for connecting the first regulation portion 251and the second regulation portion 255 is provided at a position closerto the downstream wall portion 232 than the upstream wall portion 231,and a bottom surface of the housing recess portion 427 is formed by theouter peripheral surface of the regulating connection portion 428. Likethe first regulation portion 251 and the second regulation portion 255,the regulating connection portion 428 is included in the base member261, and is integrally molded with the regulation portions 251 and 255and the like.

The outer peripheral insertion portion 426 is provided in the regulatingconnection portion 428. The outer peripheral insertion portion 426 is athrough hole that penetrates through the regulating connection portion428 in the depth direction Z, and an inner peripheral surface 426 a ofthe outer peripheral insertion portion 426 comes in contact with theouter peripheral surface of the second support portion 424. In thiscase, the movement of the second support portion 424 in the widthdirection X and the height direction Y is restricted by the innerperipheral surface 426 a of the outer peripheral insertion portion 426,and the inner peripheral surface 426 a can be referred to as apositioning surface. The downstream-side plate surface of the regulatingconnection portion 428 is in contact with the outer peripheral surfaceof the SA base portion 221. In this instance, the movement of the sensorSA 220 toward the upstream side is regulated by the downstream-sideplate surface of the regulating connection portion 428, and thedownstream-side plate surface can be referred to as a positioningsurface.

Further, as shown in FIG. 92, the housing 201 does not need to have thesealing member 206. Even in this case, the housing attachment isconfigured by the flange portion 207, and the wall thickness of thehousing attachment is not changed. The housing attachment does notnecessarily have to be thicker than the accommodation wall portion 121.

As Modification C4, in the fourth embodiment, the first regulationportion 251 and the second regulation portion 255 may be formed of amember different from the housing body 204. For example, a firstregulation member forming the first regulation portion 251 is attachedto the housing body 204. In the above configuration, the firstregulation member is formed in a plate shape. A support recess portionfor supporting the first regulation member is formed on the innerperipheral surface of the housing body 204, and the outer peripheral endof the first regulating member is fitted in the support recess portion.The first regulation member is made of a conductive metal material orthe like. Since the first regulation member has conductivity in thismanner, static electricity charged in the housing body 204 havinginsulating properties is easily discharged by the first regulatingmember. For that reason, the detection accuracy of the flow ratedetector 202 can be inhibited from being lowered by static electricity.

As Modification C5, in the first embodiment, the depth housingprotrusion 72 b of the housing body 24 may have the function of only oneof the first holding portion and the second holding portion. Forexample, in the SA side surface 126, the depth housing protrusion 72 bis in contact with a portion orthogonal to the depth direction Z. Thedepth housing protrusion 72 b with the above configuration holds thesensor SA 50 in position in the depth direction Z, and has the functionof the first holding portion, but does not have the function of thesecond holding portion.

In addition, the width housing protrusion 72 a may have the functions ofboth the first holding portion and the second holding portion. Forexample, the width housing protrusion 72 a comes in contact with aportion of the outer peripheral surface of the sensor SA 50 inclined inboth the width direction X and the depth direction Z. The width housingprotrusion 72 a with the above configuration holds the sensor SA 50 inposition in both the width direction X and the depth direction Z, andhas the functions of both the first holding portion and the secondholding portion.

As Modification C6, the third holding portion may have at least onefunction of the first holding portion and the second holding portion.For example, in the first embodiment, the region step surface 66 of thehousing body 24 is not orthogonal to the height direction Y, butinclined with respect to the height direction Y. In the aboveconfiguration, the region step surface 66 is inclined with respect tothe width direction X and the depth direction Z so as to face the innerperipheral side, and the circuit step surface 55 of the sensor SA 50 isinclined with respect to the width direction X and the depth direction Zso as to face the outer peripheral side. In this instance, since thecircuit step surface 55 enters the inside of the region step surface 66and the circuit step surface 55 comes in contact with the region stepsurface 66, the sensor SA 50 is restricted from moving not only in theheight direction Y but also in the width direction X and the depthdirection Z. For that reason, the region step surface 66 has thefunctions of the first holding portion and the second holding portion inaddition to the function of the third holding portion. The circuit stepsurface 55 and the region step surface 66 may be inclined by a taperedsurface or may be inclined by a curved surface.

As Modification C7, in the detection units which are the sensor SAs 50and 220, the portion that comes in contact with the position holder ofthe housing does not have to be located closer to the physical quantitydetector such as the flow rate detectors 22 and 202 in the detectionunit. For example, in the first embodiment, the separation distance L3between the flow rate detector 22 and the circuit step surface 55 may belarger than the separation distance L4 between the base end portion ofthe sensor SA 50 and the circuit step surface 55.

As Modification C8, the physical quantity measurement device may befixed to the intake pipe 12 a through no sealing member such as theO-ring 26 or the sealing member 206. For example, the housing has ahousing fitting portion that fits into the airflow insertion hole 12 b,and the outer peripheral surface of the housing fitting portion and theinner peripheral surface of the airflow insertion hole 12 b are in closecontact with each other. In the above configuration, the housing fittingportion is included in the housing attachment, and the position holderssuch as the accommodation wall portion 121 and the first regulationportion 251 are provided closer to the housing tip side than the housingfitting portion.

As Modification C9, the entire portion of the housing which does notenter the intake passage 12 may be the housing attachment. For example,in the fourth embodiment, in addition to the sealing holder 205 and theflange portion 207, a portion of the housing 201 which does not enterthe intake passage 12 is also included in the housing attachment. In theabove configuration, a portion of the housing body 204 facing the innerperipheral surface of the airflow insertion hole 12 b and the innerperipheral surface of the pipe flange 12 c is included in the housingattachment. Also, in the above configuration, if the first regulationportion 251 as the position holder is located closer to the housing tipside than the housing attachment, even if deformation due to resinmolding occurs in the housing attachment, the position and shape of thefirst regulation portion 251 due to the deformation can be inhibitedfrom being unintentionally changed.

As Modification C10, the housing opening may be opened in the depthdirection Z. For example, in the fourth embodiment, the housing opening241 is provided in the upstream wall portion 231 or the downstream wallportion 232 of the housing body 204. Also, in the above configuration,the sensor SA 220 can be inserted into the internal space 204 a from thehousing opening 241, and the thermosetting resin can be injected intothe internal space 204 a from the housing opening 241.

As Modification C11, three or more members may be assembled to eachother when forming the housing. For example, in the fourth embodiment,two cover members, that is, a front cover member and a back covermember, are assembled to the base member 261. In the aboveconfiguration, the front cover member is a cover member 262, and theback cover member is a member having at least a part of the back wallportion 234 of the housing body 204.

As Modification C12, not all of the detection units, which are thesensor SAs 50 and 220, may be accommodated in the internal space of thehousing. In other words, at least a part of the detection unit may beaccommodated in the internal space. For example, in the firstembodiment, the tip portions of the lead terminals 54 of the sensor SA50 protrude to the outside through the housing opening 61. Also, in theabove configuration, the member covering the lead terminals 54 isattached to the housing 21, so that the lead terminals 54 and theconnector terminals 28 a can be protected.

As Modification C13, the position holder such as the accommodation wallportion 121 and the first regulation portion 251 may be provided closerto the housing base end side than the housing attachment as long as theposition holder is separated from the housing attachment in the housing.Also, in the above configuration, since the position holder and thehousing attachment are separated from each other, even if deformationdue to resin molding occurs in the housing attachment, the position andshape of the position holder can be inhibited from changing due to thedeformation.

As Modification C14, a physical quantity detector for detecting aphysical quantity different from the flow rate of the intake air may beprovided in the measurement flow channel. Examples of the physicalquantity detector provided in the measurement flow channel include adetector for detecting a temperature, a detector for detecting ahumidity, a detector for detecting a pressure, and the like in additionto the flow rate detectors 22 and 202. Those detectors may or may not bemounted on the sensor SAs 50 and 220 as the detection units. Thephysical quantity detector not mounted on the detection unit may beattached to the inner peripheral surface of the measurement flowchannel, or may be attached to a projection portion or the likeprotruding from the inner peripheral surface of the measurement flowchannel. In addition, the physical quantity detector may be provided inthe bypass flow channels 30 and 210, not in the measurement flowchannel. In other words, the physical quantity detector may be providedin the passage flow channel.

<Modification of Configuration Group D>

As Modification D1, the mold device may have multiple passage moldportions for molding the passage flow channel. For example, in the firstembodiment, as shown in FIGS. 93 and 94, the passage flow channel 31 ofthe housing 21 is molded by the passage mold portions 431 a and 431 b.

The passage flow channel 31 with the above configuration has a throttlepassage portion 433 provided between the inflow passage 31 a and theoutflow passage 31 b. While the throttle passage portion 433 narrows thepassage flow channel 31 toward the outflow port 33 b, the outflowpassage 31 b does not narrow the passage flow channel 31 toward theoutflow port 33 b. For example, the inner peripheral surface of thethrottle passage portion 433 includes the wall throttle surface 153 a,while the inner peripheral surface of the outflow passage 31 b does notinclude the wall throttle surface 153 a. When the boundary between thethrottle passage portion 433 and the outflow passage 31 b is referred toas a throttle boundary 434, the passage flow channel 31 is not narrowedfrom the throttle boundary 434 toward either the inflow port 33 a or theoutflow port 33 b.

The mold device 90 has an inflow passage mold portion 431 a and anoutflow passage mold portion 431 b instead of the passage mold portion104 of the first embodiment. In the mold device 90, the passage moldportions 431 a and 431 b abut against each other and also abut againstthe measurement molding portion 97. The inflow passage mold portion 431a and the outflow passage mold portion 431 b abut against each other attheir respective tip end faces, and the surfaces of the respectivehousing base end sides of the passage mold portions 431 a and 431 b abutagainst the tip end face of the measurement molding portion 97.

The inflow passage mold portion 431 a and the outflow passage moldportion 431 b do not thicken toward the respective tip end faces. Forthat reason, when the mold device 90 is removed from the resin moldedhousing 21, the inflow passage mold portion 431 a can be extracted fromthe inflow port 33 a, and the outflow passage mold portion 431 b can beextracted from the outflow port 33 b. The inflow passage mold portion431 a corresponds to an inflow mold portion, and the outflow passagemold portion 431 b corresponds to an outflow mold portion.

According to the above modification, in the passage flow channel 31, aportion closer to the inflow port 33 a side than the throttle boundary434 is molded by the inflow passage mold portion 431 a, and a portioncloser to the outflow port 33 b side than the throttle boundary 434 ismolded by the outflow passage mold portion 431 b. For that reason, thereis no need to extract the inflow passage mold portion 431 a from theoutflow port 33 b, and there is no need to extract the outflow passagemold portion 431 b from the inflow port 33 a, so that the degree offreedom in design and manufacturing relating to the shape and size ofthe passage flow channel 31 can be enhanced. Moreover, since the inflowpassage mold portion 431 a can be extracted from the inflow port 33 aand the outflow passage mold portion 431 b can be extracted from theoutflow port 33 b, the inner peripheral surface of the passage flowchannel 31 can be integrally molded.

As Modification D2, in the configuration in which the positionaldeviation between the passage mold portion and the measurement moldportion is regulated by fitting the mold projection portion into themold recess portion, either the passage mold portion or the measurementmold portion may have the mold projection portion. For example, in thefifth embodiment, the measurement molding portion 97 has the moldprojection portion 334, and the passage mold portion 104 has the moldrecess portion 335, but the measurement molding portion 97 may have themold recess portion 335, and the passage mold portion 104 may have themold projection portion 334.

For example, in the first embodiment, as shown in FIG. 95, the tip endface of the passage mold portion 104 does not abut against the outerperipheral mold portions 102 and 103 but abuts against the measurementmolding portion 97. In the above configuration, in a state before themold device 90 is removed from the resin molded housing 21, themeasurement molding portion 97 is inserted between the passage moldportion 104 and the outer peripheral mold portions 102 and 103 in thepassage flow channel 31, and the tip end face of the passage moldportion 104 and the side surface of the measurement molding portion 97abut against each other. In the abutment portion, the mold projectionportion 334 is provided on the tip end face of the passage mold portion104, and the mold recess portion 335 is provided on the side surface ofthe measurement molding portion 97. In this case, unlike the firstembodiment, the measurement molding portion 97 is removed from thehousing 21 after the passage mold portion 104 has been extracted fromthe inflow port 33 a.

The configuration in which the mold projection portion fits into themold recess portion may be applied to Modification D1 described above.For example, the mold recess portion 335 is provided in each of theinflow passage mold portion 431 a and the outflow passage mold portion431 b, and the mold projection portion 334 fitted in each of the moldrecess portions 335 of the passage mold portions 431 a and 431 b isprovided in the measurement molding portion 97. One of the moldprojection portion and the mold recess portion may be provided in theinflow passage mold portion 431 a, and the other may be provided in theoutflow passage mold portion 431 b. In this case, the position deviationcan be restricted between the inflow passage mold portion 431 a and theoutflow passage mold portion 431 b in the width direction X and theheight direction Y.

As Modification D3, in the fifth embodiment, the mold recess portion 335does not have to surround the four sides of the mold projection portion334. For example, the mold recess portion 335 is opened in the widthdirection X in the passage mold portion 104. In the above configuration,the mold recess portion 335 is a groove portion extending in the widthdirection X on the inner passage surface 159, and the mold projectionportion 334 is shaped to extend along the groove portion. Also, in theabove configuration, the mold projection portion 334 enters the moldrecess portion 335, thereby restricting the relative movement betweenthe passage mold portion 104 and the measurement molding portion 97 inthe depth direction Z.

As Modification D4, the inflow port may be opened in a directioninclined with respect to the depth direction Z. For example, the inflowport may be opened obliquely to the side opposite to the housing baseend side. For example, in the fifth embodiment, as shown in FIG. 96, inthe depth direction Z, the upstream end portion of the passage floorsurface 152 is disposed at a position closer to the outflow port 33 bthan the upstream end portion of the passage ceiling surface 151.

In the above configuration, as compared with the fifth embodiment, thelength dimension of the passage floor surface 152 is reduced in thedepth direction Z, and the passage floor surface 152 is also reduced inthe height direction Y by an amount corresponding to the reduction. Forthat reason, compared with the fifth embodiment, the height dimension ofthe inflow port 33 a in the height direction Y is reduced, and a foreignmatter is less likely to enter from the inflow port 33 a by the amountof the reduction.

In the configuration in which the floor throttle surface 152 a isincluded in the passage floor surface 152, it is considered that thereis a foreign matter that can easily enter the measurement flow channel32 instead by changing the direction of advancing against the floorthrottle surface 152 a. On the other hand, in the present modification,it is assumed that as the passage floor surface 152 is longer in thedepth direction Z, the possibility that the advancing direction of theforeign matter is changed to the direction in which the foreign mattereasily enters the measurement flow channel 32 is higher, and the portiondisposed in the height direction Y is not provided at the upstream endportion of the passage ceiling surface 151 in the floor throttle surface152 a. In other words, in the floor throttle surface 152 a, a portionhaving a high possibility of changing the advancing direction of theforeign matter to a direction in which the foreign matter easily entersthe measurement flow channel 32 is deleted. This makes it possible toinhibit the foreign matter that has abutted against the floor throttlesurface 152 a from entering the measurement flow channel 32.

As Modification D5, the flow channel boundary portion 34 does not haveto face the outflow port 33 b side. For example, in the firstembodiment, the flow channel boundary portion 34 extends in the depthdirection Z similarly to the passage ceiling surface 151. In the aboveconfiguration, in the mold device 90, the boundary between themeasurement molding portion 97 and the passage mold portion 104coincides with the flow channel boundary portion 34.

As Modification D6, the passage mold portion may be extracted from theoutflow port instead of the inflow port. For example, in the firstembodiment, the passage mold portion 104 is extracted from the outflowport 33 b. In the above configuration, the passage mold portion 104 isnot thickened toward the tip portion of the passage mold portion 104 inthe same manner as in the first embodiment, but the direction in whichthe passage mold portion 104 is assembled to the outer peripheral moldportions 102 and 103 is opposite to that in the first embodiment.Further, the passage flow channel 31 is configured not to be narrowedfrom the inflow port 33 a toward the outflow port 33 b, contrary to thefirst embodiment.

As Modification C7, in the fifth embodiment, the inclination angle 83 inthe passage floor surface 152 may not be uniform depending on thelocation. Even in the above case, assuming a virtual line in which theupstream end portion and the downstream end portion of the passage floorsurface 152 are connected straight to each other, the inclination angleof the virtual line with respect to the inflow ceiling portion 332 a islarger than the inclination angle 82 of the flow channel boundaryportion 34, so that a configuration in which the passage mold portion104 can be extracted from the inflow port 33 a can be realized.

<Modifications of Configuration Group E>

As Modification E1, in the fourth embodiment, the air flow meter 200 mayhave a terminal support portion that supports the connector terminal 208a in the connector region QC. For example, as shown in FIGS. 97 to 99,in the connector region QC, a back support portion 441 as a terminalsupport portion is provided between the second terminal portion 282 band the back wall portion 234. The back support portion 441 is formed ofa synthetic resin material in a plate shape, and is bonded to the backwall portion 234 by an adhesive or the like in a state of beingsuperposed on the inner peripheral surface of the back wall portion 234.The second terminal portion 282 b abuts against the plate surface of theback support portion 441 on the housing opening 241 side. In this case,the back support portion 441 supports the second terminal portion 282 bfrom the side opposite to the housing opening 241.

The back support portion 441 is extended to the second terminal portion282 b and the lead terminal 224 in the height direction Y. In otherwords, the back support portion 441 is provided at a position ofextending across the boundary between the second terminal portion 282 band the lead terminal 224 in the height direction Y. As with the secondterminal portion 282 b, the lead terminal 224 is in contact with theplate surface of the back support portion 441 on the housing opening 241side. In this case, in addition to the second terminal portion 282 b,the back support portion 441 supports the lead terminals 224 from theside opposite to the housing opening 241.

In the housing 201, the SA main body 225 of the sensor SA 220 is caughtby the back wall 234, and the wall surface 283 of the back wall portion234 on the housing opening 241 maintains the position of the sensor SA220. In the back support portion 441, the lead terminal 224 of thesensor SA 220 is caught by the back support portion 441, and the platesurface 441 a of the back support portion 441 on the side of the housingopening 241 holds the position of the lead terminal 224. In this case,the wall surface 283 corresponds to a unit holding surface, and theplate surface 441 a corresponds to a terminal holding surface.

The back support portion 441 may be made of a metal material. The backsupport portion 441 may be formed by a part of the housing 201. Forexample, the back support portion 441 is formed by a projection portionin which the back wall portion 234 of the housing 201 protrudes towardthe housing opening 241 side. In the above configuration, the tip endface of the projection portion is the plate surface 411 a of the backsupport portion 441, and corresponds to a terminal holding surface.

According to the present modification, in the connector region QC, thesecond terminal portion 172 b is supported by the back support portion441 from the side opposite to the housing opening 241. For that reason,the second terminal portion 172 b is less likely to be unintentionallydeformed or displaced. In this case, the second terminal portion 282 bis displaced from the lead terminal 224, thereby being capable ofinhibiting the second terminal portion 282 b and the lead terminal 224from being properly joined to each other.

According to the present modification, the lead terminal 224 insertedbetween the housing opening 241 and the back support portion 441 issupported by the back support portion 441 from the side opposite to thehousing opening 241. For that reason, the lead terminal 224 is lesslikely to be unintentionally deformed or displaced. This makes itpossible to inhibit that the second terminal portion 282 b and the leadterminal 224 cannot be properly joined to each other due to thepositional deviation of the lead terminals 224 with respect to thesecond terminal portion 282 b.

According to the present modification, the plate surface 441 a of theback support portion 441 supporting the lead terminal 224 of the sensorSA 220 is disposed at a position closer to the housing opening 241 thanthe wall surface 283 of the back wall portion 234 supporting the SA mainbody 225. In this case, since there is no need to insert the joiningtool deeper than the plate surface 441 a when the second lead portion342 and the lead terminals 224 are joined to each other, the joiningtool can be inhibited from unintentionally coming in contact with thehousing 201.

As Modification E2, in the fourth embodiment, in the connection portionbetween the connector terminal 208 a and the lead terminal 224, theconnector terminal 208 a and the lead terminal 224 may be aligned not inthe width direction X and the depth direction Z but in the heightdirection Y. For example, as shown in FIGS. 97 and 98, each of thesecond terminal portion 282 b and the lead terminal 224 extends towardthe housing opening 241.

The second terminal portion 282 b configured as described above has aterminal extending portion 443 a extending from the sealing holder 205,and a terminal rising portion 443 b rising from the terminal extendingportion 443 a toward the housing opening 241. The lead terminal 224 hasa lead extending portion 444 a extending from the SA main body 225, anda lead rising portion 444 b rising from the lead extending portion 444 atoward the housing opening 241. The lead rising portion 444 b extends inthe width direction X along the terminal rising portion 443 b, and isjoined to the terminal rising portion 443 b by welding or the like. Theterminal rising portion 443 b corresponds to a vertical terminalportion.

According to the above modification, the terminal rising portion 443 bextends from the back support portion 441 toward the housing opening241. In this case, when the lead rising portion 444 b and the terminalrising portion 443 b are sandwiched between a joining tool such aswelding electrodes or the like, there is no need to insert the joiningtool into the back side of the lead rising portion 444 b and theterminal rising portion 443 b from the housing opening 241. For thatreason, when the lead rising portion 444 b and the terminal risingportion 443 b are joined to each other with the use of the joining tool,the joining operation can be facilitated.

As Modification E3, in the fourth embodiment, the lead terminal 224 andthe connector terminal 208 a may have a vent 445 as a bent portion. Forexample, as shown in FIG. 98, the lead extending portion 444 a of thelead terminal 224 and the terminal extending portion 443 a of theconnector terminal 208 a each have the vent 445. As shown in FIG. 99,each of the lead terminal 224 and the second terminal portion 282 b hasthe vent 445. In either configuration, stresses applied to the leadterminal 224 and the connector terminal 208 a can be reduced by thevents 445.

As Modification E4, similarly to Modification C3, the sensor SAs 50 and220 as the detection units may have multiple physical quantitydetectors. In Modification C3 described above, in the fourth embodiment,a configuration is exemplified in which the first detector 421 isprovided inside the housing 201, and the second detector 422 is providedoutside the housing 201. On the other hand, in the present modification,a configuration in which both the first detector 421 and the seconddetector 422 are provided inside the housing 201 will be exemplified.For example, in the fourth embodiment, as shown in FIGS. 100 and 101,the first detector 421 is disposed on the plate surface on the housingopening 241 side in the sensor SA 220, and the second detector 422 isdisposed on the plate surface on the other side to the housing opening241. In the above configuration, the first detector 421 faces the frontwall portion 233, and the second detector 422 faces the back wallportion 234.

As Modification E5, in the fourth embodiment, the sensor SA 220 and thecover member 262 may be assembled to each other, and the sensor SA 220and the cover member 262 may be collectively attached to the base member261. For example, as shown in FIG. 102, a cover unit 447 is formed byassembling the sensor SA 220 and the cover member 262 to each other, andthe cover unit 447 is attached to the base member 261. According to theabove configuration, the number of components can be reduced and thestructure of the air flow meter 200 can be simplified.

As Modification E6, the internal space of the housing may be sealed bythe cover member. For example, in the first embodiment, as shown in FIG.103, the internal space 24 a of the housing 21 is sealed by the covermember 448. In the above configuration, the potting portion 65 is notformed because the internal space 24 a is not filled with athermosetting resin. The cover member 448 is a separate member that isresin molded independently of the housing 21, and is fitted into thehousing opening 61. The internal space 24 a may be sealed by both thepotting portion 65 and the cover member 448. For example, after thepotting portion 65 has been formed by filling the internal space 24 awith the thermosetting resin, the cover member 448 is attached to thehousing opening 61.

In the fourth embodiment, as shown in FIGS. 104 and 105, the internalspace 204 a of the housing 201 is sealed with a cover member 449. In theabove configuration, a portion of the open portion of the base member261, which is not closed by the cover member 262, is not the housingopening 241 as in the fourth embodiment, but the entire open portion ofthe base member 261 is the housing opening 241. The cover member 449 isfitted into the housing opening 241 to close the entire housing opening241. The internal space 204 a may be sealed by both the potting portion242 and the cover member 449. For example, after the potting portion 242has been formed by filling the internal space 204 a with a thermosettingresin, the cover member 262 is attached to the housing opening 241.

As Modification E7, the connector terminal may protrude into the mainbody region. Even in this case, if the connector terminal does not enterbetween the detection unit and the housing opening in the direction inwhich the detection unit and the housing opening are aligned, theconnector terminal does not hinder the insertion of the detection unitinto the internal space of the housing. For example, in the firstembodiment, the connector terminals 28 a protrudes into the main bodyregion PC1, so that the second terminal portion 172 b is disposed in themain body region PC1. Also, in the above configuration, the secondterminal portion 172 b does not need to be inserted between the housingopening 61 and the sensor SA 50 in the height direction Y.

As Modification E8, in the first embodiment, the connection terminalportion 172 c of the connector terminal 28 a may be exposed to theconnector region PC2. For example, the connection terminal portion 172 cis separated from the sealing step surface 67 toward the housing opening61. Even in the above configuration, if the connection terminal portion172 c and the second terminal portion 172 b do not protrude into themain body region PC1, the terminal portions 172 b and 172 c can beinhibited from hindering the sensor SA 50 from being inserted into theinternal space 24 a.

As Modification E9, in the first embodiment, the second terminal portion172 b may extend not in the height direction Y but in the widthdirection X or the depth direction Z.

As Modification E10, the connector region may not be disposed betweenthe housing opening and the unit body in the direction in which thehousing opening and the detection unit are aligned in the internal spaceof the housing. For example, in the first embodiment, the sealing stepsurface 67 is disposed at a position farther from the housing opening 61than the lead terminal 54 in the height direction Y. In the aboveconfiguration, the connector region PC2 is aligned laterally with thesensor SA 50 in the width direction X.

As Modification E11, if the connector terminal is fixed to the housing,a part of the connector terminal does not necessarily have to beembedded in the housing. For example, the connector terminal is attachedto the housing after the housing has molded with resin with the use of amold device. Also, in the above configuration, if the physical quantitymeasurement device is configured such that the connector terminal doesnot hinder the insertion of the detection unit into the internal spaceof the housing, the detection unit can be installed in the internalspace of the housing after the connector terminal has been attached tothe housing.

<Modifications of Configuration Group F>

As Modification F1, similarly to Modification E6 described above, thedetection unit installed in the internal space of the housing may behidden from the housing opening side by the cover member. For example,in the first embodiment, as shown in FIG. 106, the sensor SA 50installed in the internal space 24 a is hidden from the housing opening61 by the cover member 448. The cover member 448 covers the connectionportion 183 in addition to the sensor SA 50. The cover member 448 has aportion that enters the internal space 24 a and a portion that overlapswith the end face of the lip 89, and the portion that enters theinternal space 24 a is fitted to the inner peripheral surface 180 of thesealing region PA.

In the above configuration, both the potting portion 65 and the covermember 448 are provided in the internal space 24 a, and the cover member448 is disposed on the other side of the sensor SA 50 across the pottingportion 65. In this case, at least one of the potting portion 65 and thecover member 448 may seal the internal space 24 a.

At the time of manufacturing the air flow meter 14, the cover member 448is used as a separate member from the housing 21, and molded with resinwith the use of a molding device or the like. After the sensor SA 50 isinstalled in the internal space 24 a of the housing 21 and the pottingportion 65 is formed by injecting a thermosetting resin into theinternal space 24 a, the cover member 448 is attached to the housing 21.In this case, the cover member 448 is fixed to the inner peripheralsurface 180 of the sealing region PA or the end face of the lip 89 withthe use of an adhesive, a molten resin, or the like.

As a configuration in which the cover member 448 covers the sensor SA 50from the housing opening 61, as shown in FIG. 107, there is aconfiguration in which the potting portion 65 is not provided. In theabove configuration, since the internal space 24 a is not sealed by thepotting portion 65, it is preferable that the cover member 262 seals theinternal space 24 a.

Further, in the fourth embodiment, as in Modification E6, as shown inFIG. 105, the sensor SA 220 installed in the internal space 204 a iscovered by the cover member 449 from the housing opening 241.

According to the above modification, the cover member 448 formed as amember different from the housing 21 is attached to the housing 21, sothat the sensor SA 50 installed in the internal space 24 a is coveredand hidden by the cover member 448. When the cover member 448 isattached to the housing 21, a pressure is hardly applied to the internalspace 24 a, so that a positional deviation of the sensor SA 50 hardlyoccurs. Therefore, the detection accuracy of the flow rate detector 22can be inhibited from varying from product to product.

As Modification F2, the housing may have a storage groove for storingthe thermosetting resin when the thermosetting resin overflows from thehousing opening. For example, in the first embodiment, as shown in FIG.108, the housing 21 has a storage groove 461 for storing the pottingmaterial 185 overflowing from the housing opening 61. The storage groove461 extends annularly along a peripheral portion of the housing opening61, and is disposed at a position separated from the lip 89 to the outerperipheral side on the side opposite to the sealing region PA across thelip 89. The storage groove 461 is provided in the housing base end face192, which is the base end face of the housing 21, and is opened in theheight direction Y.

The housing base end face 192 is formed by an outer peripheral surfaceof the housing body 24, an outer peripheral surface of the flangeportion 27, or the like, and the storage groove 461 is provided in aportion of the housing base end face 192 formed by the outer peripheralsurface of the housing body 24. The storage groove 461 may be providedin a portion of the housing base end face 192 formed by the outerperipheral surface of the flange portion 27.

In the present modification, even if the potting material 185 overflowsfrom the housing opening 61 when the potting material 185 is injectedinto the internal space 24 a, the overflowing potting material 185 isstored in the storage groove 461. For that reason, the potting material185 spreads over a wider range than the storage groove 461, and thepotting material 185 can be inhibited from adhering to an unintendedportion such as the air flow meter 14 or the work table.

As Modification F3, the housing does not have to have an open ribportion. For example, in the first embodiment, as shown in FIG. 109, thelip 89 as the open rib portion does not extend from the housing body 24,and the storage groove 461 is provided in the outer peripheral side ofthe housing opening 61, similarly to Modification F2. In the aboveconfiguration, the housing opening 61 is defined by the housing body 24rather than the lip 89, and the storage groove 461 is disposed in thehousing base end face 192. According to the above configuration, thepotting material 185 overflowing from the housing opening 61 is storedin the storage groove 461 in the same manner as in Modification F2described above.

As shown in FIG. 110, the housing 21 may not have both the lip 89 andthe storage groove 461. Also, in the above configuration, the injectionamount of the potting material 185 into the internal space 24 a isadjusted so that a liquid surface or a fluid surface of the pottingmaterial 185 does not reach the housing opening 61, thereby beingcapable of inhibiting the potting material 185 from overflowing from thehousing opening 61.

As Modification F4, the inner peripheral surface of the open rib portionand the inner peripheral surface of the housing body may not be flushwith each other, and a step may be formed between the inner peripheralsurface of the open rib portion and the inner peripheral surface of thehousing body. For example, in the first embodiment, as shown in FIG.111, the inner peripheral surface of the lip 89 is disposed on the outerperipheral side of the inner peripheral surface of the housing body 24in the inner peripheral surface 180 of the sealing region PA. In theabove configuration, an opening step surface 463 facing the housingopening 61 is formed between the inner peripheral surface of the lip 89and the inner peripheral surface of the housing body 24. The openingstep surface 463 extends annularly along the peripheral portion of thehousing opening 61 in the same manner as that of the lip 89.

According to the above configuration, when an operator injects thepotting material 185 into the internal space 24 a, it is preferable toadjust the injection amount of the potting material 185 so that thepotting material 185 does not reach the opening step surface 463. Inthis case, even if the potting material 185 reaches the opening stepsurface 463, the potting material 185 has not yet reached the housingopening 61, and the potting material 185 can be inhibited fromoverflowing from the housing opening 61 beyond the lip 89.

As Modification F5, an inner peripheral recess portion recessed in theinner peripheral surface of the housing may be provided at the open endportion of the internal space. For example, in the first embodiment, asshown in FIG. 112, an inner peripheral recess portion 464 recessed inthe inner peripheral surface 180 of the sealing region PA is provided ata position extending over the inner peripheral surface 180 and thehousing base end face 192. The inner peripheral recess portion 464 isalso open toward the housing opening 61 and extends annularly along theperipheral portion of the housing opening 61. The inner peripheralsurface of the inner peripheral recess portion 464 forms an innerperipheral surface 180.

According to the above configuration, when the operator injects thepotting material 185 into the internal space 24 a, it is preferable toadjust the injection amount of the potting material 185 so that thepotting material 185 does not reach the inner peripheral recess portion464. In this case, even if the potting material 185 reaches the innerperipheral recess portion 464, the potting material 185 has not yetreached the housing opening 61, and the potting material 185 can beinhibited from overflowing from the housing opening 61 beyond the innerperipheral recess portion 464.

Further, as shown in FIG. 113, a recess inner groove 465 for storing thepotting material 185 that has entered an inside of an inner peripheralrecess portion 464 is provided in the inner peripheral recess portion464. The recess inner groove 465 is formed in a surface of the innerperipheral surface of the inner peripheral recess portion 464 facing thehousing opening 61 side, and is opened toward the housing opening 61side. The recess inner groove 465 extends annularly along the innerperipheral recess portion 464.

According to the above configuration, a volume of the inner peripheralrecess portion 464 is increased by the volume of the recess inner groove465. For that reason, even if the potting material 185 injected into theinternal space 24 a reaches the inner peripheral recess portion 464, theinjection amount of the potting material 185 necessary until the pottingmaterial 185 reaches the housing opening 61 is increased. Therefore, theoverflow of the potting material 185 from the housing opening 61 beyondthe inner peripheral recess portion 464 is less likely to occur by thevolume of the recess inner groove 465.

As Modification F6, a chamfered portion in which the inner peripheralend of the housing base end face is chamfered may be provided at theopen end portion of the internal space. For example, in the firstembodiment, as shown in FIG. 121, a chamfered portion 466 configured bychamfering an outgoing corner portion of the housing 21 is provided soas to extend over the housing base end face 192 and the inner peripheralsurface 180. The chamfered portion 466 is a chamfered surface obtainedby chamfering an outgoing corner portion where the housing base end face192 and the inner peripheral surface 180 of the sealing region PAintersect with each other, and extends straight in the direction ofgradually expanding the sealing region PA toward the housing base endface 192 in the height direction Y. The chamfered portion 466 extendsannularly along the peripheral portion of the housing opening 61.

According to the above configuration, it is preferable to inject thepotting material 185 into the internal space 24 a until the pottingmaterial 185 reaches the chamfered portion 466 within a range in whichthe potting material 185 does not overflow from the internal space 24 a.In that case, the potting material 185 easily creeps up the chamferedportion 466, and the potting surface 193 is expanded by the amount bywhich the potting material 185 creeps up the chamfered portion 466, sothat the size of the information portion 194 to be applied to thepotting surface 193 can be increased. As a result, the visibility of theinformation portion 194 can be enhanced.

The chamfered portion 466 may be a curved surface. Examples of thecurved surface include a curved surface in which the chamfered portion466 budges toward the housing base end face 192 in the height directionY, and a curved surface in which the chamfered portion 466 is recessedtoward the housing tip end face 191.

As Modification F7, the inner peripheral curved surface of the innerperipheral surface of the housing does not necessarily have to be curvedas long as the inner peripheral curved surface is bent so as to bulgetoward the outer peripheral side. For example, the inner peripheralcurved surface may be bent at multiple locations so as to bulge towardthe outer peripheral side. Even in this case, since the two innerperipheral flat surfaces intersecting with each other are connected toeach other by the inner peripheral curved surfaces, the thermosettingresin can be inhibited from creeping up the inner peripheral surface ofthe housing when the thermosetting resin is injected into the internalspace of the housing.

As Modification F8, in the case where the filling portion such as thepotting portion 65 is formed by the filler such as the potting material185, the filler may be slowly cured at room temperature, instead offorcibly curing the filling material by applying heat.

As Modification F9, as the filler filled in the internal space of thehousing, not a thermosetting resin such as the potting material 185 isused, but a photocurable resin cured by irradiation of light or anultraviolet curable resin cured by irradiation of ultraviolet rays maybe used. As the filler, an adhesive which is hardened by exposure to airor application of water may be used. In short, the internal space may befilled with a curable resin which is cured by application of heat,light, air, water, or the like as a filler. Even in this case, thefiller filled in the internal space is cured to form the filled portion.The filler is cured to such an extent that the shape of the filler canbe maintained, thereby forming the filled portion.

<Modification of Configuration Group G>

As Modification G1, similarly to Modification F1, the internal space ofthe housing may be sealed by the cover member. For example, in the firstembodiment, a cover member is molded with a resin as a member separatefrom the housing 21, and the cover member is attached to the housing 21so as to close the internal space 24 a from the housing opening 61 side.In the above configuration, the cover member corresponds to a sealingportion, and the information portion 194 is provided on the outersurface of the cover member. Also, in the above configuration, since thehousing opening 61 and the internal space 24 a are increased in size,the outer surface of the cover member is increased in size, so that thevisibility of the information portion 194 can be enhanced.

As Modification G2, in the first embodiment, the SA main body 170 of thesensor SA 50 and the connector terminal 28 a may be aligned in the depthdirection Z. Even in this instance, when the sensor SA 50 is insertedinto the internal space 24 a from the housing opening 61, the connectorterminal 28 a can be inhibited from becoming troublesome.

As Modification G3, in the first embodiment, the housing opening 61 maynot be oriented in the height direction Y, but may be oriented in thewidth direction X or the depth direction Z. Even in this instance, it ispreferable that the housing opening 61 is disposed at a position opposedto the inflow port 33 a across the sensor SA 50 and the ring holdingportion 25 in the height direction Y. In other words, it is preferablethat the potting surface 193 is disposed outside the intake pipe 12 a ina state in which the air flow meter 14 is attached to the intake pipe 12a. As a result, the operator can visually recognize the informationportion 194 of the potting surface 193 without removing the air flowmeter 14 from the intake pipe 12 a.

<Modification of Configuration Group H>

As Modification H1, in the first embodiment, the second temperaturedetector 506 may not be mounted on the lead frame 82 as long as thesecond temperature detector 506 is disposed between the housing base endface 192 and the first temperature detector 505. For example, as shownin FIG. 114, the second temperature detector 506 is mounted on thecircuit chip 81. In the above configuration, a board of the circuit chip81 corresponds to a circuit board on which elements of the secondtemperature detector 506 are mounted. The second temperature detector506 may be mounted on the relay board 83, the lead terminal 54, or thelike.

As Modification H2, in the first embodiment, after the second correctionsignal is acquired by performing a response correction of the secondtemperature signal Sa2, a difference between the second correctionsignal and the first correction signal Sb1 may be calculated. Forexample, as shown in FIG. 115, the second correction unit 513 does notperform the response correction of the temperature differential signalSb2, but performs the response correction of the second temperaturesignal Sa2.

The second correction unit 513 calculates a second correction signalSb11 by performing the response correction of the second temperaturesignal Sa2, and outputs the second correction signal Sb11 to thetemperature differential unit 512. The second correction unit 513corrects the second temperature signal Sa2 with the use of a behavior ofchange of the second temperature signal Sa2 in the same manner as thefirst correction unit 511 corrects the first temperature signal Sa1 withthe use of the behavior of change of the first temperature signal Sa1.The second correction unit 513 uses the flow rate signal Sa3 and theflow rate transformation signal sb4 to correct the second temperaturesignal Sa2 in the same manner as the first correction unit 511 uses theflow rate signal Sa3 and the flow rate transformation signal sb4 tocorrect the first temperature signal Sa1.

Rather than calculating the differential correction signal Sb3, thetemperature differential unit 512 calculates a corrected differentialsignal Sb12 which is a difference between the first correction signalSb1 and the second correction signal Sb11. The correction amountcalculation unit 515 calculates a correction amount signal Sb5 with theuse of the corrected differential signal Sb12 and the flow ratetransformation signal sb4.

Also, in the above configuration, the second temperature signal Sa2 isused as a correction parameter for the correction of the firsttemperature signal Sa1. For that reason, even if the correction amountsignal Sb5 is calculated with the use of the corrected differentialsignal Sb12 instead of the differential correction signal Sb3, the errorof the correction value signal Sc with respect to an actual temperatureSd can be reduced. Therefore, as compared with the configuration inwhich the second correction signal Sb11 is not used for the correctionof the first temperature signal Sa1, the measurement accuracy of thecorrection value signal Sc can be improved.

As Modification H3, in the first embodiment, the response correction ofthe temperature differential signal Sb2 may not be performed. Forexample, as shown in FIG. 116, the temperature correction unit 510 doesnot have the second correction unit 513. In the above configuration, thetemperature differential signal Sb2 calculated by the temperaturedifferential unit 512 is input directly to the correction amountcalculation unit 515. Also, in the above configuration, the secondtemperature signal Sa2 is used as the correction parameter for thecorrection of the first temperature signal Sa1 similarly to ModificationH2 described above. For that reason, even if the correction amountsignal Sb5 is calculated with the use of the temperature differentialsignal Sb2 instead of the differential correction signal Sb3, an errorof the correction value signal Sc with respect to the actual temperatureSd can be reduced. Therefore, the measurement accuracy of the correctionvalue signal Sc can be enhanced in the same manner as in Modification H2described above.

As Modification H4, in the first embodiment, the second temperaturesignal Sa2 may not be used for correcting the first temperature signalSa1. For example, as shown in FIG. 117, the temperature correction unit510 does not include the temperature differential unit 512, the secondcorrection unit 513, the correction amount calculation unit 515, and thecorrection value calculation unit 516. In the above configuration, thefirst correction signal Sb1 output from the first correction unit 511 isacquired as the correction value signal Sc. Also, in the aboveconfiguration, the behavior of change of the first temperature signalSa1 and the flow rate signal Sa3 are used as the correction parametersfor the correction of the first temperature signal Sa1. For that reason,even if the second temperature signal Sa2 is not used for the correctionof the first temperature signal Sa1, the response of the correctionvalue signal Sc to the actual temperature Sd can be enhanced. In thepresent modification, the air flow meter 14 does not need to have thesecond temperature detector 506.

As Modification H5, in the first embodiment, the flow rate signal Sa3may not be used to correct the first temperature signal Sa1. Forexample, as shown in FIG. 118, the temperature correction unit 510 doesnot include the second correction unit 513, the characteristictransformation unit 514, and the correction amount calculation unit 515.In the above configuration, the correction value calculation unit 516calculates the correction value signal Sc with the use of the secondtemperature signal Sa2 instead of the correction amount signal Sb5.Also, in the above configuration, the second temperature signal Sa2 isused for correcting the first temperature signal Sa1 in the same manneras in Modification H2 described above. For that reason, even if the flowrate signal Sa3 is not used for the correction of the first temperaturesignal Sa1, the error of the correction value signal Sc with respect tothe actual temperature Sd can be reduced. In the present modification,the air flow meter 14 does not need to have the flow rate detector 22.

As Modification H6, in the first embodiment, the response correction ofthe first temperature signal Sa1 may not be performed. For example, asshown in FIG. 119, the temperature correction unit 510 does not includethe first correction unit 511, the correction amount calculation unit515, and the correction amount calculation unit 515. In the aboveconfiguration, the correction value calculation unit 516 calculates thecorrection value signal Sc with the use of the first temperature signalSa1 instead of the first correction signal Sb1. Also, in the aboveconfiguration, the second temperature signal Sa2 is used for correctingthe first temperature signal Sa1 in the same manner as in ModificationH2 described above. For that reason, even if the behavior of change ofthe first temperature signal Sa1 is not used for the correction of thefirst temperature signal Sa1, the error of the correction value signalSc with respect to the actual temperature Sd can be reduced.

As Modification H7, in the first embodiment, the correction valuecalculation unit 516 may calculate the correction value signal Sc bymultiplying a signal based on the first temperature signal Sa1 by asignal based on the second temperature signal Sa2 or the flow ratesignal Sa3 instead of integrating the signals. For example, as shown inFIG. 118, the correction value calculation unit 516 calculates thecorrection value signal Sc by multiplying the first correction signalSb1 by the temperature differential signal Sb2. As shown in FIG. 119,the correction value calculation unit 516 multiplies the firsttemperature signal Sa1 by the differential correction signal Sb3 tocalculate the correction value signal Sc.

As Modification H8, in the first embodiment, the first temperaturedetector 505 may not be mounted on the detection board 22 a of the flowrate detector 22 as long as the first temperature detector 505 isdisposed on the opposite side of the housing opening 61 across thesecond temperature detector 506 in the height direction Y. For example,the first temperature detector 505 is mounted on the relay board 83 orthe lead frame 82.

As Modification H9, in the first embodiment, at least one of the firsttemperature detector 505 and the second temperature detector 506 may notbe mounted on the sensor SA 50. For example, the first temperaturedetector 505 is embedded in the longitudinal partition wall 69 of thehousing 21, or the second temperature detector 506 is mounted on theconnector terminal 28 a.

As Modification H10, in the first embodiment, the flow rate detector 22and the first temperature detector 505 may be mounted on boardsindependent of each other as long as those detectors are provided in themeasurement flow channel 32. The flow rate detector 22 and the firsttemperature detector 505 may be disposed at positions separated fromeach other in the height direction Y. Even in this instance, since thedetection targets to be detected by the flow rate detector 22 and thefirst temperature detector 505 are intake air flowing through themeasurement flow channel 32, the response of the first temperaturesignal Sa1 using the flow rate signal Sa3 can be enhanced.

As Modification H11, in the first embodiment, the physical quantitycorrected based on its behavior of change is the temperature, but thecorrection target may be a physical quantity different from thetemperature, such as the flow rate, humidity, and pressure of the intakeair. For example, a first pressure detector for detecting a pressure isprovided in the measurement flow channel 32 as a physical quantitydetector, and a second pressure detector as the same kind-quantitydetector for detecting a physical quantity of the same kind as the firstpressure detector is disposed at a position closer to the housing baseend face 192 than the first pressure detector. In the aboveconfiguration, in the measurement control device, the first pressuresignal which is the detection result of the first pressure detector iscorrected with the use of the second pressure signal which is thedetection result of the second pressure detector.

In addition, the physical quantity measurement device has a temperaturedetector that detects a temperature as the different kind-quantitydetector that detects a physical quantity of a kind different from thepressure, and in the measurement control device, the first pressuresignal is corrected with the use of a temperature signal that is adetection result of the temperature detector. Further, in themeasurement control device, the first pressure signal is corrected withthe use of the behavior of change of the first pressure signal.According to those configurations, the accuracy of pressure measurementand the response of pressure measurement can be enhanced with respect tothe measurement of pressure as a physical quantity.

As Modification H12, in the first embodiment, the measurement controldevice for correcting the first temperature signal Sa1 may be configurednot by the circuit chip 81 but by another control device included in theair flow meter 14. In addition, the measurement control device may beprovided in an external device such as an ECU 20 in addition to the airflow meter 14. For example, the first temperature signal Sa1, the secondtemperature signal Sa2, and the flow rate signal Sa3 are input to theECU 20 from the first temperature detector 505, the second temperaturedetector 506, and the flow rate detector 202 through the circuit chip81, respectively. Further, the measurement control device may be variousarithmetic devices mounted on a vehicle, and multiple arithmetic devicesmay function as a control device in cooperation with each other. Inaddition, various programs may be stored in a non-transitory tangiblestorage medium such as a flash memory or a hard disk provided in eachcalculation device.

While the present disclosure has been described with reference toembodiments thereof, it is to be understood that the disclosure is notlimited to the embodiments and constructions. To the contrary, thepresent disclosure is intended to cover various modification andequivalent arrangements. In addition, while the various elements areshown in various combinations and configurations, which are exemplary,other combinations and configurations, including more, less or only asingle element, are also within the spirit and scope of the presentdisclosure.

What is claimed is:
 1. A physical quantity measurement device formeasuring a physical quantity of a fluid, comprising: a measurement flowchannel through which the fluid as a measurement target flows; a housingthat forms the measurement flow channel and is attached to apredetermined attaching target in a state where at least a part of thehousing is positioned inward of the attaching target; a physicalquantity detector that detects a physical quantity of the fluid in themeasurement flow channel; a same kind-quantity detector that detects, inan interior of the housing, a physical quantity of the same kind as thephysical quantity detected by the physical quantity detector, thephysical quantity detected by the same kind-quantity detector being acorrection parameter used for correcting a detection result of thephysical quantity detector; an inward part that is positioned inward ofthe attaching target; and an outward part that is positioned outward ofthe attaching target without being positioned inward of the attachingtarget, wherein the physical quantity detector is provided at a positionincluded in the inward part, and the same kind-quantity detector isprovided at a position closer to the outward part than the physicalquantity detector is in an alignment direction along which the inwardpart and the outward part are aligned.
 2. The physical quantitymeasurement device according to claim 1, wherein the same kind-quantitydetector is provided at a position included in the inward part togetherwith the physical quantity detector.
 3. The physical quantitymeasurement device according to claim 1, further comprising a detectionunit provided inside the housing, wherein the physical quantity detectorand the same kind-quantity detector are both included in the detectionunit.
 4. The physical quantity measurement device according to claim 1,further comprising a different kind-quantity detector that detects, inthe interior of the housing, a physical quantity of a different kindfrom the physical quantity detected by the physical quantity detector,the physical quantity detected by the different kind-quantity detectorbeing a correction parameter used for correction of a detection resultof the physical quantity detector.
 5. The physical quantity measurementdevice according to claim 4, wherein the physical quantity detector andthe different kind-quantity detector are both provided in themeasurement flow channel.
 6. The physical quantity measurement deviceaccording to claim 4, wherein the physical quantity detector is atemperature detector that detects a temperature as a physical quantityof the fluid, and the different kind-quantity detector is a flow ratedetector that detects a flow rate as the physical quantity of the fluid.7. A measurement control device for controlling a physical quantitymeasurement device, the physical quantity measurement device comprising:a measurement flow channel through which a fluid as a measurement targetflows; a housing that forms the measurement flow channel and is attachedto a predetermined attaching target in a state where at least a part ofthe housing is positioned inward of a predetermined attaching target; aphysical quantity detector that detects a physical quantity of the fluidin the measurement flow channel; a same kind-quantity detector thatdetects, in an interior of the housing, a physical quantity of the samekind as the physical quantity detected by the physical quantitydetector; an inward part that is positioned inward of the attachingtarget; and an outward part that is positioned outward of the attachingtarget without being positioned inward of the attaching target, whereinthe physical quantity detector is provided at a position included in theinward part, the same kind-quantity detector is provided at a positioncloser to the outward part than the physical quantity detector is in analignment direction along which the inward part and the outward part arealigned, and the measurement control device further comprises a physicalquantity correction unit that corrects a detection result of thephysical quantity detector based on a detection result of the samekind-quantity detector.
 8. The measurement control device according toclaim 7, wherein the physical quantity correction unit includes adifferential correction unit that acquires a differential correctionamount for correcting the detection result of the physical quantitydetector based on a difference between the detection result of thephysical quantity detector and the detection result of the samekind-quantity detector.
 9. The measurement control device according toclaim 8, wherein the differential correction unit increases thedifferential correction amount with increase of the difference.
 10. Themeasurement control device according to claim 7, wherein the physicalquantity correction unit includes a change correction unit that correctsthe detection result of the physical quantity detector based on abehavior of change of the detection result of the physical quantitydetector.
 11. The measurement control device according to claim 7,wherein the physical quantity measurement device includes a differentkind-quantity detector that detects a physical quantity of a differentkind from the physical quantity detected by the physical quantitydetector and the same kind-quantity detector, and the physical quantitycorrection unit includes a different king-quantity correction unit thatcorrects the detection result of the physical quantity detector based ona detection result of the different kind-quantity detector in additionto the detection result of the same kind-quantity detector.
 12. Themeasurement control device according to claim 7, wherein the physicalquantity detector and the same kind-quantity detector are each atemperature detector that detects a temperature as the physical quantityof the fluid.
 13. A measurement control device for controlling aphysical quantity measurement device, the physical quantity measurementdevice including: a measurement flow channel through which a fluid as ameasurement target flows; a housing that forms the measurement flowchannel and is attached to a predetermined attaching target; and aphysical quantity detector that detects a physical quantity of the fluidin the measurement flow channel, the measurement control devicecomprising a controller configured to correct a detection result of thephysical quantity detector based on a behavior of change of thedetection result of the physical quantity detector.
 14. The measurementcontrol device according to claim 13, wherein the physical quantitymeasurement device includes a different kind-quantity detector thatdetects a physical quantity of a different kind from the physicalquantity detected by the physical quantity detector, and the controllercorrects the detection result of the physical quantity detector based ona detection result of the different kind-quantity detector in additionto the behavior of change of the detection result of the physicalquantity detector.
 15. The measurement control device according to claim14, wherein the physical quantity detector is a temperature detectorthat detects a temperature as the physical quantity of the fluid, thedifferent kind-quantity detector is a flow rate detector that detects aflow rate as the physical quantity of the fluid, and the controllercorrects a temperature signal, which is the detection result of thephysical quantity detector, based on a behavior of change of thetemperature signal and a flow rate signal which is the detection resultof the different kind-quantity detector.
 16. The measurement controldevice according to claim 15, wherein the controller increases a flowrate correction amount with decrease in flow rate which is the detectionresult of the different kind-quantity detector, for correcting thetemperature which is the detection result of the physical quantitydetector.